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@josephdpurcell
josephdpurcell / mysqlbup.cron
Created February 20, 2014 13:55
Rotating Daily and Weekly MySQL Dump Cron
# mysqlbup.cron by josephdpurcell
#
# This cron will export all databases every day at 4am. Those exports are
# automatically rotating from servername.com.day0 to servername.com.day6 so you
# always have a bup of the last 7 days of backups.
#
# Also, this cron will export all databases every week for the last 4 weeks at
# 2am on Sunday. Those exports are automatically rotating from
# servername.com.week0 to servername.com.week3 so you always have a bup of the
# last 4 weeks of backups.
@jboner
jboner / latency.txt
Last active June 18, 2024 12:10
Latency Numbers Every Programmer Should Know
Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns 14x L1 cache
Mutex lock/unlock 25 ns
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy 3,000 ns 3 us
Send 1K bytes over 1 Gbps network 10,000 ns 10 us
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD