Re: oracle database running on NAS through iscsi
- From: David Robillard <david.robillard@xxxxxxxxx>
- To: Betsy Ward <wardbe@xxxxxxxxxxx>
- Date: Thu, 21 Oct 2010 17:32:01 -0400
Hello Betsy,
This is a rather old post of yours, but...
> Does anyone on this list have their Oracle databases sitting on a NAS that
> runs through ISCSI?
We're also running Oracle RAC 11gR2 on iSCSI. Both nodes are Sun X4170
machines running RedHat 5.5 x86_64 with ASM disks iSCSI connected to a
clustered Sun Unified Storage 7410. The 7410 has a 100 GB SSD acting
as optimized read cache and two mirrored 18 GB SSDs acting as
optimized write cache. The 7410 is also used for general purpose
storage.
What did you use to determine that performance has not been good?
Maybe I can reproduce it here and compare numbers with you?
Here are some general performance tips with iSCSI storage:
- use dedicated interfaces for your iSCSI connections (i.e. isolate
the storage traffic from any other kind of traffic).
- use port aggregation to bundle two or more interfaces and dedicate
them to storage traffic only (be sure to use the right LACP mode in
order to use both interfaces simultaneously instead of just an
active-passive setup!).
- use a dedicated non-routable storage-only VLAN for all iSCSI traffic.
- do not oversubscribe the storage switch ports.
- if possible, use a pair of storage dedicated switches at a minimum
of 1 GbE. 10 GbE if you can afford it (and really need it).
- use jumbo frames on the storage VLAN.
- use a single iSCSI target per LUN.
There are probably some kernel and/or Oracle and/or ASM parameters
that can be tuned to increase iSCSI performance, but alas, I don't
know them.
HTH,
David
> If yes, I'm curious as to the performance you are
> experiencing with it and whether you can share that with me possibly how you
> tuned your database to work on such a setup?
>
> We are running Oracle 11g db servers on Red Hat 5.3 connected to a Sun
> X4540 "Thor" running nexenta. We moved to this configuration about a year
> ago and performance has not been good. The X4540 also has our email servers
> storage on it, so when they tuned it they tuned it for write times to be
> fast, not reads.
>
> But I'm wondering if there are things I can do from the database side to be
> able to speed up the performance because of the slowness on the hardware
> side, or if the sysadmin just needs to get the thing tuned well for reads so
> that Oracle is happy?
>
> TIA,
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