Stripe sizes with gstripe
dkelly at hiwaay.net
Fri Jun 13 14:28:12 UTC 2008
On Fri, Jun 13, 2008 at 09:08:48AM +0200, Wojciech Puchar wrote:
> >>Does gstripe read an entire stripe at a time? If so, why do that instead
> >>just reading a few requested blocks? If not, then is there any advantage
> >>to large stripes?
> >Apparently it won't read anything larger than your stripe size which
> >defaults to a miserable 4k.
> depending from what's needed, but unless i need just huge linear transfer,
> i set stripe size to something huge, like 256MB.
> then single read is rarely split on 2 disks, while multiple reads have
> good chances to touch different drives
Come to think of it I didn't try setting the stripe size larger than the
ATA max transaction size of 128k.
Still, I don't understand what is going on when I use md5(1) on a
gigabyte file hosted on a gstripe partition with 128k stripes that
"systat -v" reports transactions are usually between 42k and 43k each?
On a non-striped filesystem the same operation runs 126k to 127k
Transfer bandwidth seems to be limited by the number of transactions per
second more than the size of the transaction.
David Kelly N4HHE, dkelly at HiWAAY.net
Whom computers would destroy, they must first drive mad.
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