Re: iostat with raid device...
From: Linux Raid Study <hidden>
Date: 2011-04-11 09:36:50
The initial recovery should normally be done during first few minutes .... this is a newly formatted disk so there isn't any user data there. So, if I run the IO benchmark after say 3-4 min of doing, I should be ok? mdam --create /dev/md0 --raid5.... mount /dev/md0 /mnt/raid mkfs.ext4 /mnt/raid ...wait 3-4 min run IO benchmark... Am I correct? Thanks. On Mon, Apr 11, 2011 at 2:25 AM, Robin Hill [off-list ref] wrote:
On Mon Apr 11, 2011 at 01:32:34 -0700, Linux Raid Study wrote:quoted
On Sat, Apr 9, 2011 at 1:50 AM, Robin Hill [off-list ref] wrote:quoted
On Fri Apr 08, 2011 at 05:40:46PM -0700, Linux Raid Study wrote:quoted
What I'm not sure of is if the device is newly formatted, would raid recovery happen? What else could explain difference in the first run of IO benchmark?When an array is first created, it's created in a degraded state - this is the simplest way to make it available to the user instantly. The final drive(s) are then automatically rebuilt, calculating the parity/data information as normal for recovering a drive.Thanks. So, the uneven (unequal) distribution of Wrtie/Sec numbers in the iostat output are ok...is that correct?If it hadn't completed the initial recovery, yes. If it _had_ completed the initial recovery then I'd expect writes to be balanced (barring any differences in hardware). Cheers, Robin -- ___ ( ' } | Robin Hill [off-list ref] | / / ) | Little Jim says .... | // !! | "He fallen in de water !!" |
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