FS of choice for max random iops ( Maildir )

Terje Elde terje at elde.net
Fri Sep 16 21:47:15 UTC 2011

On 16. sep. 2011, at 16:18, freebsd at top-consulting.net wrote:
> zpool create data da1
> zfs create data/maildomains
> zfs set sync=disabled data/maildomains

Just for the archives... sync=disabled won't disable disable the zil, it'll disable waiting for a disk-flush on fsync etc. With a battery backed controller cache, those flushes should go to cache, and be pretty mich free. You end up tossing away something for nothing. 

You're getting about half the performance on a sequential write to the zfs, as you get with raw ufs. That makes perfect sense, doesn't it?

Ufs writes raw, zfs writes to zil, then final restingplace forthe data. Account for the seeks between, and you're seeing what you should. 

Move the zil if you don't want both those sets of writes on the same array, or do what Svein said, and get funk^w logical. 

(a tad simplified, but I think the logic will hold. (yes, pun intended))


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