Re: Quorum drive and Data Drive on the Shared Array
- From: "John Fullbright [MVP]" <fjohn@donotspamnetappdotcom>
- Date: Sat, 10 Jun 2006 19:33:44 -0700
What are the best practices for SQL these days in terms of response time?
In any event bufflatch waits and write log waits would be an indication that
there is a disk bottleneck. To answer the question, something that won't
load the array to the point where you exceed the response times in the best
practices.
This brings up a point about SAN storage in general. The ability to pool
storage and divy chunks out to various servers is great, but it also
introduces a potential problem; comingling. Comingling happens when IO
against one LUN impacts IO against another LUN that shares the same physical
spindles. The problem gets really difficult to troubleshoot in scenarios
where multiple servers connect to the same storage device. Today, you have
to design the array to account for peak load on all the LUNs that share the
same spindles. With IO intensive applications like SQL or Exchange, this
often results in situations where the spindle count is driven by the
performance requirement and you end up with unused space. When you design
storage, you have to consider both space and performance.
"Abbie" <Abbie@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:8A53E644-BC2C-40AD-9E2E-66033202207B@xxxxxxxxxxxxxxxx
In the situation where I CAN present a1gb lun and another 145gb lun from a
146gb mirror, and if sql server will be the only application, what is the
best use for thie 145gb lun with performance in mind? database backups?
tlog
backups?
excuse the typing, broken radius, got screws and a plate yesterday.
cheers!
-abbie
"Russ Kaufmann [MVP]" wrote:
"Abbie" <Abbie@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:54385CCE-1243-4598-B246-FEF4A4765955@xxxxxxxxxxxxxxxx
When building an active/passive sql2k cluster (win2k3), should you:
a)create a phyical mirror just for the quorum (lots of wasted space)
b)create a 1gb(or so) logical from physical mirror
It depends on the hardware. Some lower end SANs will not let you break
physical disks down inside the SAN into smaller LUNs. For example, if you
have two 146 GB drives, you can create a 1 GB LUN and a 145 GB LUN out of
the two disks (in a mirror in the SAN) which are then presented to the
cluster nodes as two basic disks of 1 GB and 145 GB. However, some lower
end
SANs will not let you break the physical disks down. Then, you can create
only a 146 GB LUN and would have tons of wasted space.
--
Russ Kaufmann
MVP - Windows Server - Clustering
ClusterHelp.com, a Microsoft Certified Gold Partner
Web http://www.clusterhelp.com
Blog http://msmvps.com/clusterhelp
.
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- From: Russ Kaufmann [MVP]
- Re: Quorum drive and Data Drive on the Shared Array
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