[DRBD-user] How do multiple drbd devices affect performance?
lmb at suse.de
Thu Feb 5 17:18:07 CET 2009
On 2009-02-05T16:25:00, George Negoita <negoita.george at gmail.com> wrote:
> I'm building a cheap iscsi storage. I have two nodes with 1,4GB storage each
> and I'm thinking of two ways of doing this:
> 1. 3ware raid controller -> one big drbd device -> lvm -> export volumes via
> 2. 3ware raid controller -> lvm -> multiple drbd devices -> export via iscsi
> What's the safest/fastest method?
> Will multiple drbd devices affect performance? There should be no more than
> 8-10 drbd devices in this setup (if I stick to the second method). I'm
> tempted to go with the second one because it seems safer (for example, if I
> have problems with one drbd volume, I can still use the others). What's your
1,4GB? Did you mean TB? ;-)
You'd get the penalty of several activity logs with 2; with 1., you'd
get competition in the activity log from the various iSCSI devices.
But I'd personally lean towards 1. - drbd on top of a RAID10, and then
LVM. It is less complex and thus less likely to fail and easier to
Or, if you want to use both nodes in an active/active scenario, I'd go
with a mix - 50% each, replicated to the other node. You may get higher
performance that way.
Teamlead Kernel, SuSE Labs, Research and Development
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde
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