Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Take a look at the disk throughput of this two disk software RAID 1 array in a Linux 2.6.26-2-686 Debian system :

Disk throughput per device

As you can see, one device reads at a speed apparently close to its top throughput while the other writes likewise. What is happening ?

share|improve this question
up vote 0 down vote accepted
10:44 root@kivu /var/log# grep resync *
dmesg:[    6.950037] md: resync of RAID array md0
dmesg:[    6.950037] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for resync.
kern.log:Aug  1 18:18:25 kivu kernel: [    6.950037] md: resync of RAID array md0
kern.log:Aug  1 18:18:25 kivu kernel: [    6.950037] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for resync.
kern.log:Aug  2 01:02:47 kivu kernel: [28104.777816] md: md0: resync done.

There - that was a RAID resynchronization, triggered shortly after a reboot.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .