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| HDPARM(8) System Manager's Manual HDPARM(8) | |
| NAME | |
| hdparm - get/set SATA/IDE device parameters | |
| SYNOPSIS | |
| hdparm [options] [device ...] | |
| DESCRIPTION | |
| hdparm provides a command line interface to various kernel interfaces supported by the | |
| Linux SATA/PATA/SAS "libata" subsystem and the older IDE driver subsystem. Many newer | |
| (2008 and later) USB drive enclosures now also support "SAT" (SCSI-ATA Command Transla‐ | |
| tion) and therefore may also work with hdparm. E.g. recent WD "Passport" models and | |
| recent NexStar-3 enclosures. Some options may work correctly only with the latest ker‐ | |
| nels. | |
| OPTIONS | |
| When no options are given, -acdgkmur is assumed. For "Get/set" options, a query without | |
| the optional parameter (e.g. -d) will query (get) the device state, and with a parameter | |
| (e.g., -d0) will set the device state. | |
| -a Get/set sector count for filesystem (software) read-ahead. This is used to | |
| improve performance in sequential reads of large files, by prefetching additional | |
| blocks in anticipation of them being needed by the running task. Many IDE drives | |
| also have a separate built-in read-ahead function, which augments this filesystem | |
| (software) read-ahead function. | |
| -A Get/set the IDE drive's read-lookahead feature (usually ON by default). Usage: | |
| -A0 (disable) or -A1 (enable). | |
| -b Get/set bus state. | |
| -B Get/set Advanced Power Management feature, if the drive supports it. A low value | |
| means aggressive power management and a high value means better performance. Pos‐ | |
| sible settings range from values 1 through 127 (which permit spin-down), and val‐ | |
| ues 128 through 254 (which do not permit spin-down). The highest degree of power | |
| management is attained with a setting of 1, and the highest I/O performance with a | |
| setting of 254. A value of 255 tells hdparm to disable Advanced Power Management | |
| altogether on the drive (not all drives support disabling it, but most do). | |
| -c Get/set (E)IDE 32-bit I/O support. A numeric parameter can be used to enable/dis‐ | |
| able 32-bit I/O support. Currently supported values include 0 to disable 32-bit | |
| I/O support, 1 to enable 32-bit data transfers, and 3 to enable 32-bit data trans‐ | |
| fers with a special sync sequence required by many chipsets. The value 3 works | |
| with nearly all 32-bit IDE chipsets, but incurs slightly more overhead. Note that | |
| "32-bit" refers to data transfers across a PCI or VLB bus to the interface card | |
| only; all (E)IDE drives still have only a 16-bit connection over the ribbon cable | |
| from the interface card. | |
| -C Check the current IDE power mode status, which will always be one of unknown | |
| (drive does not support this command), active/idle (normal operation), standby | |
| (low power mode, drive has spun down), or sleeping (lowest power mode, drive is | |
| completely shut down). The -S, -y, -Y, and -Z options can be used to manipulate | |
| the IDE power modes. | |
| -d Get/set the "using_dma" flag for this drive. This option now works with most com‐ | |
| binations of drives and PCI interfaces which support DMA and which are known to | |
| the kernel IDE driver. It is also a good idea to use the appropriate -X option in | |
| combination with -d1 to ensure that the drive itself is programmed for the correct | |
| DMA mode, although most BIOSs should do this for you at boot time. Using DMA | |
| nearly always gives the best performance, with fast I/O throughput and low CPU | |
| usage. But there are at least a few configurations of chipsets and drives for | |
| which DMA does not make much of a difference, or may even slow things down (on | |
| really messed up hardware!). Your mileage may vary. | |
| --dco-freeze | |
| DCO stands for Device Configuration Overlay, a way for vendors to selectively dis‐ | |
| able certain features of a drive. The --dco-freeze option will freeze/lock the | |
| current drive configuration, thereby preventing software (or malware) from chang‐ | |
| ing any DCO settings until after the next power-on reset. | |
| --dco-identify | |
| Query and dump information regarding drive configuration settings which can be | |
| disabled by the vendor or OEM installer. These settings show capabilities of the | |
| drive which might be disabled by the vendor for "enhanced compatibility". When | |
| disabled, they are otherwise hidden and will not show in the -I identify output. | |
| For example, system vendors sometimes disable 48_bit addressing on large drives, | |
| for compatibility (and loss of capacity) with a specific BIOS. In such cases, | |
| --dco-identify will show that the drive is 48_bit capable, but -I will not show | |
| it, and nor will the drive accept 48_bit commands. | |
| --dco-restore | |
| Reset all drive settings, features, and accessible capacities back to factory | |
| defaults and full capabilities. This command will fail if DCO is frozen/locked, | |
| or if a -Np maximum size restriction has also been set. This is EXTREMELY DANGER‐ | |
| OUS and will very likely cause massive loss of data. DO NOT USE THIS COMMAND. | |
| --direct | |
| Use the kernel's "O_DIRECT" flag when performing a -t timing test. This bypasses | |
| the page cache, causing the reads to go directly from the drive into hdparm's buf‐ | |
| fers, using so-called "raw" I/O. In many cases, this can produce results that | |
| appear much faster than the usual page cache method, giving a better indication of | |
| raw device and driver performance. | |
| --drq-hsm-error | |
| VERY DANGEROUS, DON'T EVEN THINK ABOUT USING IT. This option causes hdparm to | |
| issue an IDENTIFY command to the kernel, but incorrectly marked as a "non-data" | |
| command. This results in the drive being left with its DataReQust(DRQ) line | |
| "stuck" high. This confuses the kernel drivers, and may crash the system immedi‐ | |
| ately with massive data loss. The option exists to help in testing and fortifying | |
| the kernel against similar real-world drive malfunctions. VERY DANGEROUS, DO NOT | |
| USE!! | |
| -D Enable/disable the on-drive defect management feature, whereby the drive firmware | |
| tries to automatically manage defective sectors by relocating them to "spare" sec‐ | |
| tors reserved by the factory for such. Control of this feature via the -D option | |
| is not supported for most modern drives since ATA-4; thus this command may fail. | |
| -E Set cd/dvd drive speed. This is NOT necessary for regular operation, as the drive | |
| will automatically switch speeds on its own. But if you want to play with it, | |
| just supply a speed number after the option, usually a number like 2 or 4. This | |
| can be useful in some cases, though, to smooth out DVD video playback. | |
| -f Sync and flush the buffer cache for the device on exit. This operation is also | |
| performed internally as part of the -t and -T timings and other options. | |
| --fallocate | |
| This option currently works only on ext4 and xfs filesystem types. When used, | |
| this must be the only option given. It requires two parameters: the desired file | |
| size in kilo-bytes (byte count divided by 1024), followed by the pathname for the | |
| new file. It will create a new file of the specified size, but without actually | |
| having to write any data to the file. This will normally complete very quickly, | |
| and without thrashing the storage device. | |
| E.g. Create a 10KByte file: hdparm --fallocate 10 temp_file | |
| --fibmap | |
| When used, this must be the only option given. It requires a file path as a | |
| parameter, and will print out a list of the block extents (sector ranges) occupied | |
| by that file on disk. Sector numbers are given as absolute LBA numbers, refer‐ | |
| enced from sector 0 of the physical device rather than from the partition or | |
| filesystem. This information can then be used for a variety of purposes, such as | |
| examining the degree of fragmenation of larger files, or determining appropriate | |
| sectors to deliberately corrupt during fault-injection testing procedures. | |
| This option uses the new FIEMAP (file extent map) ioctl() when available, and | |
| falls back to the older FIBMAP (file block map) ioctl() otherwise. Note that | |
| FIBMAP suffers from a 32-bit block-number interface, and thus not work beyond 8TB | |
| or 16TB. FIBMAP is also very slow, and does not deal well with preallocated | |
| uncommitted extents in ext4/xfs filesystems, unless a sync() is done before using | |
| this option. | |
| --fwdownload | |
| When used, this should be the only option given. It requires a file path immedi‐ | |
| ately after the option, indicating where the new drive firmware should be read | |
| from. The contents of this file will be sent to the drive using the (S)ATA DOWN‐ | |
| LOAD MICROCODE command, using either transfer protocol 7 (entire file at once), | |
| or, if the drive supports it, transfer protocol 3 (segmented download). This com‐ | |
| mand is EXTREMELY DANGEROUS and could destroy both the drive and all data on it. | |
| DO NOT USE THIS COMMAND. The --fwdownload-mode3 , --fwdownload-mode3-max , and | |
| --fwdownload-mode7 variations on basic --fwdownload allow overriding automatic | |
| protocol detection in favour of forcing hdparm to use a specific transfer proto‐ | |
| col, for testing purposes only. | |
| -F Flush the on-drive write cache buffer (older drives may not implement this). | |
| -g Display the drive geometry (cylinders, heads, sectors), the size (in sectors) of | |
| the device, and the starting offset (in sectors) of the device from the beginning | |
| of the drive. | |
| -h Display terse usage information (help). | |
| -H Read the temperature from some (mostly Hitachi) drives. Also reports if the tem‐ | |
| perature is within operating condition range (this may not be reliable). Does not | |
| cause the drive to spin up if idle. | |
| -i Display the identification info which the kernel drivers (IDE, libata) have stored | |
| from boot/configuration time. This may differ from the current information | |
| obtainable directly from the drive itself with the -I option. The data returned | |
| may or may not be current, depending on activity since booting the system. For a | |
| more detailed interpretation of the identification info, refer to AT Attachment | |
| Interface for Disk Drives, ANSI ASC X3T9.2 working draft, revision 4a, April | |
| 19/93, and later editions. | |
| --idle-immediate | |
| Issue an ATA IDLE_IMMEDIATE command, to put the drive into a lower power state. | |
| Usually the device remains spun-up. | |
| --idle-unload | |
| Issue an ATA IDLE_IMMEDIATE_WITH_UNLOAD command, to unload or park the heads and | |
| put the drive into a lower power state. Usually the device remains spun-up. | |
| -I Request identification info directly from the drive, which is displayed in a new | |
| expanded format with considerably more detail than with the older -i option. | |
| --Istdin | |
| This is a special variation on the -I option, which accepts a drive identification | |
| block as standard input instead of using a /dev/hd* parameter. The format of this | |
| block must be exactly the same as that found in the /proc/ide/*/hd*/identify | |
| "files", or that produced by the --Istdout option described below. This variation | |
| is designed for use with collected "libraries" of drive identification informa‐ | |
| tion, and can also be used on ATAPI drives which may give media errors with the | |
| standard mechanism. When --Istdin is used, it must be the *only* parameter given. | |
| --Istdout | |
| This option dumps the drive's identify data in hex to stdout, in a format similar | |
| to that from /proc/ide/*/identify, and suitable for later use with the --Istdin | |
| option. | |
| -J Get/set the Western Digital (WD) Green Drive's "idle3" timeout value. This time‐ | |
| out controls how often the drive parks its heads and enters a low power consump‐ | |
| tion state. The factory default is eight (8) seconds, which is a very poor choice | |
| for use with Linux. Leaving it at the default will result in hundreds of thou‐ | |
| sands of head load/unload cycles in a very short period of time. The drive mecha‐ | |
| nism is only rated for 300,000 to 1,000,000 cycles, so leaving it at the default | |
| could result in premature failure, not to mention the performance impact of the | |
| drive often having to wake-up before doing routine I/O. | |
| WD supply a WDIDLE3.EXE DOS utility for tweaking this setting, and you should use | |
| that program instead of hdparm if at all possible. The reverse-engineered imple‐ | |
| mentation in hdparm is not as complete as the original official program, even | |
| though it does seem to work on at a least a few drives. A full power cycle is | |
| required for any change in setting to take effect, regardless of which program is | |
| used to tweak things. | |
| A setting of 30 seconds is recommended for Linux use. Permitted values are from 8 | |
| to 12 seconds, and from 30 to 300 seconds in 30-second increments. Specify a | |
| value of zero (0) to disable the WD idle3 timer completely (NOT RECOMMENDED!). | |
| -k Get/set the "keep_settings_over_reset" flag for the drive. When this flag is set, | |
| the drive will preserve the -dmu settings over a soft reset, (as done during the | |
| error recovery sequence). This option defaults to off, to prevent drive reset | |
| loops which could be caused by combinations of -dmu settings. The -k option | |
| should therefore only be set after one has achieved confidence in correct system | |
| operation with a chosen set of configuration settings. In practice, all that is | |
| typically necessary to test a configuration (prior to using -k) is to verify that | |
| the drive can be read/written, and that no error logs (kernel messages) are gener‐ | |
| ated in the process (look in /var/log/messages on most systems). | |
| -K Set the drive's "keep_features_over_reset" flag. Setting this enables the drive | |
| to retain the settings for -APSWXZ over a soft reset (as done during the error | |
| recovery sequence). Not all drives support this feature. | |
| -L Set the drive's doorlock flag. Setting this to 1 will lock the door mechanism of | |
| some removable hard drives (e.g. Syquest, ZIP, Jazz..), and setting it to 0 will | |
| unlock the door mechanism. Normally, Linux maintains the door locking mechanism | |
| automatically, depending on drive usage (locked whenever a filesystem is mounted). | |
| But on system shutdown, this can be a nuisance if the root partition is on a | |
| removable disk, since the root partition is left mounted (read-only) after shut‐ | |
| down. So, by using this command to unlock the door after the root filesystem is | |
| remounted read-only, one can then remove the cartridge from the drive after shut‐ | |
| down. | |
| -m Get/set sector count for multiple sector I/O on the drive. A setting of 0 dis‐ | |
| ables this feature. Multiple sector mode (aka IDE Block Mode), is a feature of | |
| most modern IDE hard drives, permitting the transfer of multiple sectors per I/O | |
| interrupt, rather than the usual one sector per interrupt. When this feature is | |
| enabled, it typically reduces operating system overhead for disk I/O by 30-50%. | |
| On many systems, it also provides increased data throughput of anywhere from 5% to | |
| 50%. Some drives, however (most notably the WD Caviar series), seem to run slower | |
| with multiple mode enabled. Your mileage may vary. Most drives support the mini‐ | |
| mum settings of 2, 4, 8, or 16 (sectors). Larger settings may also be possible, | |
| depending on the drive. A setting of 16 or 32 seems optimal on many systems. | |
| Western Digital recommends lower settings of 4 to 8 on many of their drives, due | |
| tiny (32kB) drive buffers and non-optimized buffering algorithms. The -i option | |
| can be used to find the maximum setting supported by an installed drive (look for | |
| MaxMultSect in the output). Some drives claim to support multiple mode, but lose | |
| data at some settings. Under rare circumstances, such failures can result in mas‐ | |
| sive filesystem corruption. | |
| --make-bad-sector | |
| Deliberately create a bad sector (aka. "media error") on the disk. EXCEPTIONALLY | |
| DANGEROUS. DO NOT USE THIS OPTION!! This can be useful for testing of device/RAID | |
| error recovery mechanisms. The sector number is given as a (base10) parameter | |
| after the option. Depending on the device, hdparm will choose one of two possible | |
| ATA commands for corrupting the sector. The WRITE_LONG works on most drives, but | |
| only up to the 28-bit sector boundary. Some very recent drives (2008) may support | |
| the new WRITE_UNCORRECTABLE_EXT command, which works for any LBA48 sector. If | |
| available, hdparm will use that in preference to WRITE_LONG. The WRITE_UNCOR‐ | |
| RECTABLE_EXT command itself presents a choice of how the new bad sector should | |
| behave. By default, it will look like any other bad sector, and the drive may | |
| take some time to retry and fail on subsequent READs of the sector. However, if a | |
| single letter f is prepended immediately in front of the first digit of the sector | |
| number parameter, then hdparm will issue a "flagged" WRITE_UNCORRECTABLE_EXT, | |
| which causes the drive to merely flag the sector as bad (rather than genuinely | |
| corrupt it), and subsequent READs of the sector will fail immediately (rather than | |
| after several retries). Note also that the --repair-sector option can be used to | |
| restore (any) bad sectors when they are no longer needed, including sectors that | |
| were genuinely bad (the drive will likely remap those to a fresh area on the | |
| media). | |
| -M Get/set Automatic Acoustic Management (AAM) setting. Most modern harddisk drives | |
| have the ability to speed down the head movements to reduce their noise output. | |
| The possible values are between 0 and 254. 128 is the most quiet (and therefore | |
| slowest) setting and 254 the fastest (and loudest). Some drives have only two lev‐ | |
| els (quiet / fast), while others may have different levels between 128 and 254. | |
| At the moment, most drives only support 3 options, off, quiet, and fast. These | |
| have been assigned the values 0, 128, and 254 at present, respectively, but inte‐ | |
| ger space has been incorporated for future expansion, should this change. | |
| -n Get or set the "ignore_write_errors" flag in the driver. Do NOT play with this | |
| without grokking the driver source code first. | |
| -N Get/set max visible number of sectors, also known as the Host Protected Area set‐ | |
| ting. Without a parameter, -N displays the current setting, which is reported as | |
| two values: the first gives the current max sectors setting, and the second shows | |
| the native (real) hardware limit for the disk. The difference between these two | |
| values indicates how many sectors of the disk are currently hidden from the oper‐ | |
| ating system, in the form of a Host Protected Area (HPA). This area is often used | |
| by computer makers to hold diagnostic software, and/or a copy of the originally | |
| provided operating system for recovery purposes. Another possible use is to hide | |
| the true capacity of a very large disk from a BIOS/system that cannot normally | |
| cope with drives of that size (eg. most current {2010} BIOSs cannot deal with | |
| drives larger than 2TB, so an HPA could be used to cause a 3TB drive to report | |
| itself as a 2TB drive). To change the current max (VERY DANGEROUS, DATA LOSS IS | |
| EXTREMELY LIKELY), a new value should be provided (in base10) immediately follow‐ | |
| ing the -N option. This value is specified as a count of sectors, rather than the | |
| "max sector address" of the drive. Drives have the concept of a temporary | |
| (volatile) setting which is lost on the next hardware reset, as well as a more | |
| permanent (non-volatile) value which survives resets and power cycles. By | |
| default, -N affects only the temporary (volatile) setting. To change the perma‐ | |
| nent (non-volatile) value, prepend a leading p character immediately before the | |
| first digit of the value. Drives are supposed to allow only a single permanent | |
| change per session. A hardware reset (or power cycle) is required before another | |
| permanent -N operation can succeed. Note that any attempt to set this value may | |
| fail if the disk is being accessed by other software at the same time. This is | |
| because setting the value requires a pair of back-to-back drive commands, but | |
| there is no way to prevent some other command from being inserted between them by | |
| the kernel. So if it fails initially, just try again. Kernel support for -N is | |
| buggy for many adapter types across many kernel versions, in that an incorrect | |
| (too small) max size value is sometimes reported. As of the 2.6.27 kernel, this | |
| does finally seem to be working on most hardware. | |
| --offset | |
| Offsets to given number of GiB (1024*1024*1024) when performing -t timings of | |
| device reads. Speed changes (about twice) along many mechanical drives. Usually | |
| the maximum is at the beginning, but not always. Solid-state drives (SSDs) should | |
| show similar timings regardless of offset. | |
| -p Attempt to reprogram the IDE interface chipset for the specified PIO mode, or | |
| attempt to auto-tune for the "best" PIO mode supported by the drive. This feature | |
| is supported in the kernel for only a few "known" chipsets, and even then the sup‐ | |
| port is iffy at best. Some IDE chipsets are unable to alter the PIO mode for a | |
| single drive, in which case this option may cause the PIO mode for both drives to | |
| be set. Many IDE chipsets support either fewer or more than the standard six (0 | |
| to 5) PIO modes, so the exact speed setting that is actually implemented will vary | |
| by chipset/driver sophistication. Use with extreme caution! This feature | |
| includes zero protection for the unwary, and an unsuccessful outcome may result in | |
| severe filesystem corruption! | |
| -P Set the maximum sector count for the drive's internal prefetch mechanism. Not all | |
| drives support this feature, and it was dropped from the offical spec as of ATA-4. | |
| --prefer-ata12 | |
| When using the SAT (SCSI ATA Translation) protocol, hdparm normally prefers to use | |
| the 16-byte command format whenever possible. But some USB drive enclosures don't | |
| work correctly with 16-byte commands. This option can be used to force use of the | |
| smaller 12-byte command format with such drives. hdparm will still revert to | |
| 16-byte commands for things that cannot be done with the 12-byte format (e.g. sec‐ | |
| tor accesses beyond 28-bits). | |
| -q Handle the next option quietly, suppressing normal output (but not error mes‐ | |
| sages). This is useful for reducing screen clutter when running from system | |
| startup scripts. Not applicable to the -i or -v or -t or -T options. | |
| -Q Get or set the device's command queue_depth, if supported by the hardware. This | |
| only works with 2.6.xx (or later) kernels, and only with device and driver combi‐ | |
| nations which support changing the queue_depth. For SATA disks, this is the | |
| Native Command Queuing (NCQ) queue depth. | |
| -r Get/set read-only flag for the device. When set, Linux disallows write operations | |
| on the device. | |
| -R Get/set Write-Read-Verify feature, if the drive supports it. Usage: -R0 (disable) | |
| or -R1 (enable). This feature is intended to have the drive firmware automati‐ | |
| cally read-back any data that is written by software, to verify that the data was | |
| successfully written. This is generally overkill, and can slow down disk writes | |
| by as much as a factor of two (or more). | |
| --read-sector | |
| Reads from the specified sector number, and dumps the contents in hex to standard | |
| output. The sector number must be given (base10) after this option. hdparm will | |
| issue a low-level read (completely bypassing the usual block layer read/write | |
| mechanisms) for the specified sector. This can be used to definitively check | |
| whether a given sector is bad (media error) or not (doing so through the usual | |
| mechanisms can sometimes give false positives). | |
| --repair-sector | |
| This is an alias for the --write-sector option. VERY DANGEROUS. | |
| -s Enable/disable the power-on in standby feature, if supported by the drive. VERY | |
| DANGEROUS. Do not use unless you are absolutely certain that both the system BIOS | |
| (or firmware) and the operating system kernel (Linux >= 2.6.22) support probing | |
| for drives that use this feature. When enabled, the drive is powered-up in the | |
| standby mode to allow the controller to sequence the spin-up of devices, reducing | |
| the instantaneous current draw burden when many drives share a power supply. Pri‐ | |
| marily for use in large RAID setups. This feature is usually disabled and the | |
| drive is powered-up in the active mode (see -C above). Note that a drive may also | |
| allow enabling this feature by a jumper. Some SATA drives support the control of | |
| this feature by pin 11 of the SATA power connector. In these cases, this command | |
| may be unsupported or may have no effect. | |
| -S Put the drive into idle (low-power) mode, and also set the standby (spindown) | |
| timeout for the drive. This timeout value is used by the drive to determine how | |
| long to wait (with no disk activity) before turning off the spindle motor to save | |
| power. Under such circumstances, the drive may take as long as 30 seconds to | |
| respond to a subsequent disk access, though most drives are much quicker. The | |
| encoding of the timeout value is somewhat peculiar. A value of zero means "time‐ | |
| outs are disabled": the device will not automatically enter standby mode. Values | |
| from 1 to 240 specify multiples of 5 seconds, yielding timeouts from 5 seconds to | |
| 20 minutes. Values from 241 to 251 specify from 1 to 11 units of 30 minutes, | |
| yielding timeouts from 30 minutes to 5.5 hours. A value of 252 signifies a time‐ | |
| out of 21 minutes. A value of 253 sets a vendor-defined timeout period between 8 | |
| and 12 hours, and the value 254 is reserved. 255 is interpreted as 21 minutes | |
| plus 15 seconds. Note that some older drives may have very different interpreta‐ | |
| tions of these values. | |
| -t Perform timings of device reads for benchmark and comparison purposes. For mean‐ | |
| ingful results, this operation should be repeated 2-3 times on an otherwise inac‐ | |
| tive system (no other active processes) with at least a couple of megabytes of | |
| free memory. This displays the speed of reading through the buffer cache to the | |
| disk without any prior caching of data. This measurement is an indication of how | |
| fast the drive can sustain sequential data reads under Linux, without any filesys‐ | |
| tem overhead. To ensure accurate measurements, the buffer cache is flushed during | |
| the processing of -t using the BLKFLSBUF ioctl. | |
| -T Perform timings of cache reads for benchmark and comparison purposes. For mean‐ | |
| ingful results, this operation should be repeated 2-3 times on an otherwise inac‐ | |
| tive system (no other active processes) with at least a couple of megabytes of | |
| free memory. This displays the speed of reading directly from the Linux buffer | |
| cache without disk access. This measurement is essentially an indication of the | |
| throughput of the processor, cache, and memory of the system under test. | |
| --trim-sector-ranges | |
| For Solid State Drives (SSDs). EXCEPTIONALLY DANGEROUS. DO NOT USE THIS OPTION!! | |
| Tells the drive firmware to discard unneeded data sectors, destroying any data | |
| that may have been present within them. This makes those sectors available for | |
| immediate use by the firmware's garbage collection mechanism, to improve schedul‐ | |
| ing for wear-leveling of the flash media. This option expects one or more sector | |
| range pairs immediately after the option: an LBA starting address, a colon, and a | |
| sector count (max 65535), with no intervening spaces. EXCEPTIONALLY DANGEROUS. DO | |
| NOT USE THIS OPTION!! | |
| E.g. hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz | |
| --trim-sector-ranges-stdin | |
| Identical to --trim-sector-ranges above, except the list of lba:count pairs is | |
| read from stdin rather than being specified on the command line. This can be used | |
| to avoid problems with excessively long command lines. It also permits batching | |
| of many more sector ranges into single commands to the drive, up to the currently | |
| configured transfer limit (max_sectors_kb). | |
| -u Get/set the interrupt-unmask flag for the drive. A setting of 1 permits the | |
| driver to unmask other interrupts during processing of a disk interrupt, which | |
| greatly improves Linux's responsiveness and eliminates "serial port overrun" | |
| errors. Use this feature with caution: some drive/controller combinations do not | |
| tolerate the increased I/O latencies possible when this feature is enabled, | |
| resulting in massive filesystem corruption. In particular, CMD-640B and RZ1000 | |
| (E)IDE interfaces can be unreliable (due to a hardware flaw) when this option is | |
| used with kernel versions earlier than 2.0.13. Disabling the IDE prefetch feature | |
| of these interfaces (usually a BIOS/CMOS setting) provides a safe fix for the | |
| problem for use with earlier kernels. | |
| -v Display some basic settings, similar to -acdgkmur for IDE. This is also the | |
| default behaviour when no options are specified. | |
| -V Display program version and exit immediately. | |
| --verbose | |
| Display extra diagnostics from some commands. | |
| -w Perform a device reset (DANGEROUS). Do NOT use this option. It exists for | |
| unlikely situations where a reboot might otherwise be required to get a confused | |
| drive back into a useable state. | |
| --write-sector | |
| Writes zeros to the specified sector number. VERY DANGEROUS. The sector number | |
| must be given (base10) after this option. hdparm will issue a low-level write | |
| (completely bypassing the usual block layer read/write mechanisms) to the speci‐ | |
| fied sector. This can be used to force a drive to repair a bad sector (media | |
| error). | |
| -W Get/set the IDE/SATA drive's write-caching feature. | |
| -X Set the IDE transfer mode for (E)IDE/ATA drives. This is typically used in combi‐ | |
| nation with -d1 when enabling DMA to/from a drive on a supported interface | |
| chipset, where -X mdma2 is used to select multiword DMA mode2 transfers and -X | |
| sdma1 is used to select simple mode 1 DMA transfers. With systems which support | |
| UltraDMA burst timings, -X udma2 is used to select UltraDMA mode2 transfers | |
| (you'll need to prepare the chipset for UltraDMA beforehand). Apart from that, | |
| use of this option is seldom necessary since most/all modern IDE drives default to | |
| their fastest PIO transfer mode at power-on. Fiddling with this can be both need‐ | |
| less and risky. On drives which support alternate transfer modes, -X can be used | |
| to switch the mode of the drive only. Prior to changing the transfer mode, the | |
| IDE interface should be jumpered or programmed (see -p option) for the new mode | |
| setting to prevent loss and/or corruption of data. Use this with extreme caution! | |
| For the PIO (Programmed Input/Output) transfer modes used by Linux, this value is | |
| simply the desired PIO mode number plus 8. Thus, a value of 09 sets PIO mode1, 10 | |
| enables PIO mode2, and 11 selects PIO mode3. Setting 00 restores the drive's | |
| "default" PIO mode, and 01 disables IORDY. For multiword DMA, the value used is | |
| the desired DMA mode number plus 32. for UltraDMA, the value is the desired | |
| UltraDMA mode number plus 64. | |
| -y Force an IDE drive to immediately enter the low power consumption standby mode, | |
| usually causing it to spin down. The current power mode status can be checked | |
| using the -C option. | |
| -Y Force an IDE drive to immediately enter the lowest power consumption sleep mode, | |
| causing it to shut down completely. A hard or soft reset is required before the | |
| drive can be accessed again (the Linux IDE driver will automatically handle issu‐ | |
| ing a reset if/when needed). The current power mode status can be checked using | |
| the -C option. | |
| -z Force a kernel re-read of the partition table of the specified device(s). | |
| -Z Disable the automatic power-saving function of certain Seagate drives (ST3xxx mod‐ | |
| els?), to prevent them from idling/spinning-down at inconvenient times. | |
| ATA Security Feature Set | |
| These switches are DANGEROUS to experiment with, and might not work with some kernels. | |
| USE AT YOUR OWN RISK. | |
| --security-help | |
| Display terse usage info for all of the --security-* options. | |
| --security-freeze | |
| Freeze the drive's security settings. The drive does not accept any security com‐ | |
| mands until next power-on reset. Use this function in combination with --secu‐ | |
| rity-unlock to protect drive from any attempt to set a new password. Can be used | |
| standalone, too. No other options are permitted on the command line with this | |
| one. | |
| --security-unlock PWD | |
| Unlock the drive, using password PWD. Password is given as an ASCII string and is | |
| padded with NULs to reach 32 bytes. The applicable drive password is selected | |
| with the --user-master switch (default is "user" password). No other options are | |
| permitted on the command line with this one. | |
| --security-set-pass PWD | |
| Lock the drive, using password PWD (Set Password) (DANGEROUS). Password is given | |
| as an ASCII string and is padded with NULs to reach 32 bytes. Use the special | |
| password NULL to set an empty password. The applicable drive password is selected | |
| with the --user-master switch (default is "user" password) and the applicable | |
| security mode with the --security-mode switch. No other options are permitted on | |
| the command line with this one. | |
| --security-disable PWD | |
| Disable drive locking, using password PWD. Password is given as an ASCII string | |
| and is padded with NULs to reach 32 bytes. The applicable drive password is | |
| selected with the --user-master switch (default is "user" password). No other | |
| options are permitted on the command line with this one. | |
| --security-erase PWD | |
| Erase (locked) drive, using password PWD (DANGEROUS). Password is given as an | |
| ASCII string and is padded with NULs to reach 32 bytes. Use the special password | |
| NULL to represent an empty password. The applicable drive password is selected | |
| with the --user-master switch (default is "user" password). No other options are | |
| permitted on the command line with this one. | |
| --security-erase-enhanced PWD | |
| Enhanced erase (locked) drive, using password PWD (DANGEROUS). Password is given | |
| as an ASCII string and is padded with NULs to reach 32 bytes. The applicable | |
| drive password is selected with the --user-master switch (default is "user" pass‐ | |
| word). No other options are permitted on the command line with this one. | |
| --user-master USER | |
| Specifies which password (user/master) to select. Defaults to user password. | |
| Only useful in combination with --security-unlock, --security-set-pass, --secu‐ | |
| rity-disable, --security-erase or --security-erase-enhanced. | |
| u user password | |
| m master password | |
| --security-mode MODE | |
| Specifies which security mode (high/maximum) to set. Defaults to high. Only use‐ | |
| ful in combination with --security-set-pass. | |
| h high security | |
| m maximum security | |
| THIS FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR OWN RISK. | |
| FILES | |
| /etc/hdparm.conf | |
| BUGS | |
| As noted above, the -m sectcount and -u 1 options should be used with caution at first, | |
| preferably on a read-only filesystem. Most drives work well with these features, but a | |
| few drive/controller combinations are not 100% compatible. Filesystem corruption may | |
| result. Backup everything before experimenting! | |
| Some options (e.g. -r for SCSI) may not work with old kernels as necessary ioctl()'s were | |
| not supported. | |
| Although this utility is intended primarily for use with SATA/IDE hard disk devices, sev‐ | |
| eral of the options are also valid (and permitted) for use with SCSI hard disk devices | |
| and MFM/RLL hard disks with XT interfaces. | |
| The Linux kernel up until 2.6.12 (and probably later) doesn't handle the security unlock | |
| and disable commands gracefully and will segfault and in some cases even panic. The secu‐ | |
| rity commands however might indeed have been executed by the drive. This poor kernel be‐ | |
| haviour makes the PIO data security commands rather useless at the moment. | |
| Note that the "security erase" and "security disable" commands have been implemented as | |
| two consecutive PIO data commands and will not succeed on a locked drive because the sec‐ | |
| ond command will not be issued after the segfault. See the code for hints how patch it | |
| to work around this problem. Despite the segfault it is often still possible to run two | |
| instances of hdparm consecutively and issue the two necessary commands that way. | |
| AUTHOR | |
| hdparm has been written by Mark Lord <mlord@pobox.com>, the original primary developer | |
| and maintainer of the (E)IDE driver for Linux, and current contributer to the libata sub‐ | |
| system, along with suggestions and patches from many netfolk. | |
| The disable Seagate auto-powersaving code is courtesy of Tomi Leppikan‐ | |
| gas(tomilepp@paju.oulu.fi). | |
| Security freeze command by Benjamin Benz, 2005. | |
| PIO data out security commands by Leonard den Ottolander, 2005. Some other parts by Ben‐ | |
| jamin Benz and others. | |
| SEE ALSO | |
| http://www.t13.org/ Technical Committee T13 AT Attachment (ATA/ATAPI) Interface. | |
| http://www.serialata.org/ Serial ATA International Organization. | |
| http://www.compactflash.org/ CompactFlash Association. | |
| Version 9.48 June 2015 HDPARM(8) |
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