Kelly Lesperance wrote:
I did some additional testing - I stopped Kafka on the host, and kicked off a disk check, and it ran at the expected speed overnight. I started kafka this morning, and the raid check's speed immediately dropped down to ~2000K/Sec.
I then enabled the write-back cache on the drives (hdparm -W1 /dev/sd*). The raid check is now running between 100000K/Sec and 200000K/Sec, and has been for several hours (it fluctuates, but seems to stay within that range). Write-back cache is NOT enabled for the drives on the hosts we haven't upgraded yet, but the speeds are similar (I kicked off a raid check on one of our CentOS 6 hosts as well, the window seems to be 150000
- 200000K/Sec on that host).
<snip> Perhaps I missed where you answered this: is this software RAID, or hardware? And I think you said you're upgrading existing boxes?
mark