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date: Wed, 7 Jun 2006 09:36:02 -0700,
group: microsoft.public.exchange.design
back
Re: excahnge best practice regarding SAN volume expansion
It really boils down to two potential issues: downtime and performance. The
impact vaies depending on the specific SAN architecture. On NetApp wich is
probably a best case scenario, if you are not clustered, you can expand a
LUN on the fly with no downtime. When you expand the LUN, there will likely
be performance impact. In a cluster, the disk resource will briefly go
offline during the expansion, so there is some downtime also. It's a nice
feature, and it beats evacuating the LUN, destroying it, creating a new LUN
and restoring the data, but as a best practice I would have to say start
with the full size.
"Mike" wrote in message
news:C12B3F4E-D162-42E4-8D18-4205C78DBD54@microsoft.com...
> The vendor will certainly say that they can expand the LUN and then
> present
> it to exchange. This action is typical on file servers and I'm sure poses
> no
> issues, but we all know that exchange is a different beast when it comes
> to
> storage requirements. Just because the vendor says they can and have done
> it, doesn't mean that it is best practice to do that. Similar to running
> exchange with circular logging turned on. Yes you can run exchange with
> circular logging on, and under most circumstances, especially in small
> environments, will pose no issues, HOWEVER, it is not a recommended best
> practice. That is what I would like to know regarding SAN volume
> expansion.
> Is it best practice to do so?
>
> Thanks
>
> Mike
>
> "John Fullbright [MVP]" wrote:
>
>> Depends on the storage. Some vendors require you to run external
>> utilities
>> and/or take the LUN down during expansion. Depending on the
>> virualization
>> layer there may be a need for contiguous space at the end of the volume.
>> In
>> some cases there are performance considerations. I think it's something
>> you
>> need to talk with your SAN vendor about.
>>
>>
>> "Mike" wrote in message
>> news:7E2DB70C-3E7F-4D5C-A74E-3A51D6190E52@microsoft.com...
>> > We are in the process of switching over to using SAN storage for
>> > exchange
>> > 2003. Our storage guys have said that if we have a LUN that is
>> > presented
>> > to
>> > exchange that is 100gb in size and in 6 months we need more space, they
>> > can
>> > thru the storage system expand the volume of the LUN and thus when that
>> > LUN
>> > is then presented to exchange it is now 200gb.
>> >
>> > Is this a recommended practice or should we be asking the strorage guys
>> > for
>> > the 200gb now and not try to expand the LUN?
>> >
>> > Thanks
>> >
>> > Mike
>>
>>
>>
date: Wed, 7 Jun 2006 21:32:41 -0700
author: John Fullbright [MVP] fjohn@donotspamnetappdotcom
Re: excahnge best practice regarding SAN volume expansion
I agree with John that it should be best practice to start with the size you
think you will need at the end. But I want to let you know that I haven't
seen any issues expanding LUNs using HP EVA 5000 or 8000 when Exchange was
running as well.
Eric
"John Fullbright [MVP]" wrote:
> It really boils down to two potential issues: downtime and performance. The
> impact vaies depending on the specific SAN architecture. On NetApp wich is
> probably a best case scenario, if you are not clustered, you can expand a
> LUN on the fly with no downtime. When you expand the LUN, there will likely
> be performance impact. In a cluster, the disk resource will briefly go
> offline during the expansion, so there is some downtime also. It's a nice
> feature, and it beats evacuating the LUN, destroying it, creating a new LUN
> and restoring the data, but as a best practice I would have to say start
> with the full size.
>
>
> "Mike" wrote in message
> news:C12B3F4E-D162-42E4-8D18-4205C78DBD54@microsoft.com...
> > The vendor will certainly say that they can expand the LUN and then
> > present
> > it to exchange. This action is typical on file servers and I'm sure poses
> > no
> > issues, but we all know that exchange is a different beast when it comes
> > to
> > storage requirements. Just because the vendor says they can and have done
> > it, doesn't mean that it is best practice to do that. Similar to running
> > exchange with circular logging turned on. Yes you can run exchange with
> > circular logging on, and under most circumstances, especially in small
> > environments, will pose no issues, HOWEVER, it is not a recommended best
> > practice. That is what I would like to know regarding SAN volume
> > expansion.
> > Is it best practice to do so?
> >
> > Thanks
> >
> > Mike
> >
> > "John Fullbright [MVP]" wrote:
> >
> >> Depends on the storage. Some vendors require you to run external
> >> utilities
> >> and/or take the LUN down during expansion. Depending on the
> >> virualization
> >> layer there may be a need for contiguous space at the end of the volume.
> >> In
> >> some cases there are performance considerations. I think it's something
> >> you
> >> need to talk with your SAN vendor about.
> >>
> >>
> >> "Mike" wrote in message
> >> news:7E2DB70C-3E7F-4D5C-A74E-3A51D6190E52@microsoft.com...
> >> > We are in the process of switching over to using SAN storage for
> >> > exchange
> >> > 2003. Our storage guys have said that if we have a LUN that is
> >> > presented
> >> > to
> >> > exchange that is 100gb in size and in 6 months we need more space, they
> >> > can
> >> > thru the storage system expand the volume of the LUN and thus when that
> >> > LUN
> >> > is then presented to exchange it is now 200gb.
> >> >
> >> > Is this a recommended practice or should we be asking the strorage guys
> >> > for
> >> > the 200gb now and not try to expand the LUN?
> >> >
> >> > Thanks
> >> >
> >> > Mike
> >>
> >>
> >>
>
>
>
date: Fri, 9 Jun 2006 02:01:01 -0700
author: Eric Aarts
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