Re: Yet Another mkfs.xfs RAID Question

[Walt H <waltabbyh@xxxxxxxxxxx>]

Christian Guggenberger wrote:
> Hi,
>
> I'm going to set up a new 1.7 TB HW Raid 5 next week.
> RAID 5 contains 11 disks, Stripe Unit should be (according to the manual)
> 128k.
> so my mkfs.xfs options will be sunit=256, swidth=2560 for the data section, 
> won't they?
>
> I will definitly use internal log, so I'd like to ask, if I should use
> logversion 2, and what sunit and swidth values I should use here?
> I guess the same as for the data section???
>
> Would I gain something from logversion 2?
>
> thx
> Christian

Are you using software md raid or hardware raid? If it's hardware raid 
5, the logversion argument shouldn't matter. Software raid is another 
story. I recently setup a file/database server with a six disk software 
raid 5 setup. I had time to try different raid chunksizes as well as 
experiment with version 1 vs. version 2 logs. What I found, for my case, 
version 2 logs for xfs really helped out in create/delete operations. 
Particularly deletes. Sequential read/writes were unaffected by the 
version differences. I ran many Bonnie++ runs as well as created a 
script that created 2000 directories with 10000 files in each directory 
and then proceeded to delete the whole lot. Each result was timed, 
although I don't have any numbers for you. I remember version 2 logs as 
performing much better for these types of uses. HTH,

-Walt