Chris J. Bednar writes:
> An external log is scary to me; I can afford lackluster
>write performance easier than I can afford:
> ``You know that $16k RAID setup you bought? it's gone to Hell
> because the one disk I was using for the log croaked.''
I think the idea is that you put the log on a RAID1 device.
> ``You know that big RAID system? Well, I moved it from one
> machine to another, and now it won't work.''
You can even put the log onto a different partition of your existing
RAID5 disks. eg. RAID5 on /dev/sd*1 and RAID1 over /dev/sda2 + /dev/sdb2.
Obviously this'll get you less performance as the log and data are
going to the same disks, but it may make it more cohesive and portable
for you. You still gain in that xfs and md don't have to go through
hoops to write journal-sized chunks and data-sized chunks to the same
place any more. At least that's what I understand from reading this list.
This may be more of a gain when NFS is involved?
I have yet to try it out - but will soon :)