Estimate time for disk expansion...

[edmund_6]

Ive adding a 72G drive to a raid 5 which is made up of 3 X 72G.
Now im wondering how long on average do you think this expansion would take.I know the rule of thumb is 15mins per G...I also read on another thread here saying it took 9 days.
Thats a long time without a backup.(I presume you cant run a backup while its expanding or can you...)
Ive got a ML370 and my contoller is a smart array 532.
Also if i want the minimum impact on a network,would it be better to set the priorty high when expanding,so it would expand faster or set it low and let the user be able to use the server and let the expand take much longer to do.Or can you change priorites during the expansion.I ask this becuase my only outage window would be a weekend..
Last question does the extending the logical drive in ACU take a long time ?
Any feedback would be appreciated..
Thanks in advance...
cheers

[Steven Clementi]

Edmund:

Depending on how much data needs to be moved around, it could take an hour or it can take hours (and in some cases days).

Sure you can do a backup. You will decrease the preformance of the expansion as you "utilize" the disks by reading them for the backup, but there is no reason why a backup can't run.

If you can kick off the expansion at night or during non-usage hours then yes, setting the priority should help out a bit. Can it be changed during the process? I think it can. I remember doing this a few weeks ago with a 5i controller, but don't remember if it was actually doing the expand yet.

Expanding a Logical drive should not take long. I can not quote any tested results, but it does depend on how much more space your allocating to the logical drive. Adding only 1GB should happen within minutes while adding 100GB might take 15-30 minutes before it's usable, maybe even more.



Steven

[e4services]

Yes, this is all true. Best practice is while offline or in low usage. Set the priority to High while running and set it back again. Depending on the other activity, this can make a big difference.

[edmund_6]

Thanks for the feedback.So this is how im going to attack this expansion.

1.Ensure i get a backup.(This server runs sharepoint and im gonna use veritas as well as msdmback to backup the database)

2.Insert extra disk with server on.Fire up ACU and add the disk to the arrary with the priority set to high.

3.Wait for that to finish..hopefully by the end of the weekend.If done by monday,use ACU to extend the logical drive and then use diskpart to add extra space to my exisitng d drive.

Is there anything im missing.

I guess if i get errored out when adding the disk to arrary.i'll update firmware and re do the above steps and that should fix any errors if any..right ?

Let me know if this is the best plan of attack...

cheers

[Steven Clementi]

I would suggest doing the firmware first. It is usually always better to have the most up to date SA controller firmware and driver before doing things like this. It is not required unless the firmware is really old, but still.

If you plan on upgrading the firmware/driver afterwards anyway... do it first and get it out of the way.


Steven

[edmund_6]

Thanks for the feedback.Last couple of questions.How much available space would i be able to add if you take into account the parity.what % of the 72G would i have.
Also while its expanding users would still be able to work off that server right, it will just be a little bit slower becuase of re-striping thats happening

Thanks

[edmund_6]

Update..

I started my the array expansion Last saturday afternoon.
It has now completed 5 days later...
anyways just to confirm i will then need to use ACU again to extend the logical drive right ?
Does this procedure take long ?
I also came across a thread saying you will need to convert your disk from basic to dynamic before you can extend it in windows disk manager.Is this is a must ?
any feedbackup would be great

Thanks

[Steven Clementi · Accepted solution]

Yes, you use ACU again. Extending the Logical drive should not take as long as expanding an Array since you are not moving alot of data around, just telling the LUN it can utilize more available space.

Depending on how your disk is currently configured, you may or may not need dynamic disk. The one thing I didn't ask, that i usually do, is how is the original array carved up? Do you have 1 Logical drive service your C: partition and other partitions? or do you have a logical drive for each windows drive configured?

I ask because, you can not extend any partition on a logical drive that has the system partition on it (usually the c: drive). You would need to use other 3rd party software, NOT diskpart.

If your c: drive is a seperate logical drive, then depending on your data disk configuration, you may or may not need to be dynamic disk. More specifically, if you have a logical drive that only has Data on it, but it has 2 partitions say.... D: and E:, then as a basic disk, you would only be able to extend the E: partition, but as a dynamic disk, you should be able to extend the d: partition as well. (using Diskpart).


So to answer the question, it is usually not a must, but greatly depends on your current config.


Click below for more info on Diskpart.exe...

http://support.microsoft.com/default.aspx?scid=kb;en-us;325590


Steven

[edmund_6]

Thanks Steven for the prompt reply...
Yes it has only one arrary and it has 2 logical drive.c and d.Its D drive which i want to add this extra space.So that should be fine right.the disk is basic.I wouldnt need to convert to dynamic.. ?
I will have a read thru that link u posted...
So just to confirm once the extending logical drive in ACU is done, i shoudl be able to see the free space in disk management in windows as being available right behind my d drive.I will then just need to extend the slider or use diskpart..

cheers

[Steven Clementi]

Yes, you should be good to go with diskpart. You do not need to upgrade to dynamic, read the KB article carefully. Diskpart works with BOTH Basic and Dynamic disks.


Yes, you should see "free Space" at the end (all the way to the right) of the drive in Disk Manager. There is no slider that Ican recall unless maybe you have some sort of add in.


Once you have diskpart, you run it and it puts you into a shell type program, sort of like NSLOOKUP or FTP or TELNET, etc.

Basically, you need to...

LIST VOLUME - to list the volumes you have on that disk

SELECT VOLUME # - to select the volume you need to extend

EXTEND - to extend the partition.


Steven

[edmund_6]

Cheers Steven...

Ive just been onsite and ive started the Logical drive expansion in acu.It gave me an option of how much i want to extend it by and it gave me a maximum limit which i selected.so its in progress..From responses on other threads as well..it should take about and hr or so right ?.
So once thats done ..ill have an outage and then restart into safemode..an use diskpart to add this space..right ?

cheers to those that have contributed..

[Steven Clementi]

You do NOT need an outage. Diskpart works ON ThE fLy!


It is suggested that you have minimul disk activity, but you do not need safemode.


Steven

[Steven Clementi]

Actually.. the whole process should not need an outage. You should ge able to get from A to Z while the server is online and working the WHOLE time.


Sometimes Windows does freak out though requiring a reboot, but thats expected of Windows. ;o)



Steven

[edmund_6]

Hey Steven..

U thought u had heard the last of me..
Well just thought I'l let you know ive run the extend logical drive via acu and i thought this part should only take an hr or so.Well it been 5 hours and its only on 36%.
Ive got a friend who is doing exactly the same procedure as me and it took him about 4 days for the logical drive to extend...
Is this part gong to be just as long as the extending the array which took me 5 days ?
mmmm..lets hope not... cause i did promise this client this part should be done soon..

cheers

[Steven Clementi]

Have you set the expand priority to high?

5hours = 36%

so theoretically..

10 hours = 72%
15 hours = 108%

I have never experienced a logical drive expansion take that long, but I guess it could be possible.

I can almost guarantee that the diskpart step should only be able 10 seconds and even though the process is NOT data disruptive, I do hope you have a backup of the data. You should ALWAYS have a backup.


Steven

[edmund_6]

Hi Steven

Its monday mornig and ive just checked my disk expansion and it reached 100% in extending the logical drive.It now has the bewlo message in the status screen...

# 785 Background parity initialization is currently queued or in progress on logical drive 1 ( RAID 5 in array A). If background parity initialization is queued, it will start when I/O is performed on the drive. When background parity initialization completes, the performance of the logical drive will improve


when i go to disk manager, i can see the available space now behind my logical drive...
Can i just used diskpart now or do i have to wait for the above initialization thingy to finish..Ive come this far and its takedn 10 days..i wouldnt want to screw it up by not finishing right..

cheers

[Steven Clementi]

You should be good to go. The background partiy init is just a check to make sure things are ok. Smart Arrays do that occasionally, especially after you futz with a logical drive.


It usually does not kick off until AFTER you touch the space, so I think the best thing to do is use diskpart, which should kick off the BPI.


Steven

[edmund_6]

All done..thanks heaps....thanks steven for the prompt replies..much appreciated..

[Steven Clementi]

ANytime.