[Linux-cluster] SAN, software raid, iscsi or GNBD, GFS
Markus at hochholdinger.net
Tue Aug 12 18:04:46 UTC 2008
Am Donnerstag, 7. August 2008 14:28 schrieb Alex:
> I would like to build a SAN using cheap hardware.
> Let say that we have N computers (N>8) exporting their volumes (volX, where
> X=N) using ataoe or iscsi or gnbd protocol. Each volX is arround 120GB.
i'm in a similar situation. I've a setup with gnbd (with "No Cluster"
configuration) and i'm trying to switch to aoe, because i read that aoe
should perform better.
Well, my tests indicate a very poor performance for aoe! I setup gnbd without
great hassle and tweaking. Performance is as fast as the network and the
disks can handle.
First, with aoe i had very poor performance. I had to use latest aoe module,
latest vblade and a lot of network tweaking (jumbo frames, ..) to have nearly
the performance from gnbd. OK, with reads i'm a litter faster with aoe.
But the drawback is that vblade needs a lot more cpu than gnbd_serv! So if you
export more than one block device with aoe your performance will drop.
> - Using iSCSI also allows a much more seemless transition to a hardware
> shared storage solution later on
> - GNBD seems to be slower then ISCSI and lot of work that needs to be done
> for GNBD to reach its full speed potential.
Have you tested this? As far as i can tell (my tests are over two years old)
iscsi needed much more cpu and had less performance than gnbd.
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