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expanding RAID5 set

graeme welsh
Occasional Advisor

expanding RAID5 set

hi,

we have a server Proliant ML530, 5300 RAID Controller. due to disk space issues, 2 extra disks were bought, have just tried to add these extra disks to a RAID5 set, hoping that the D:\ would be automatically extended, became apparent that this was not the case, with a warning sayin that data loss could occur.
how can this D: be expanded? disks are not dynamic, i was wondering if it was possible to run the array configuration outside of windows (during bootup), would windows then automatically see a bigger drive?
i think the only option is to backup the data, wipe the array, recreate new array, then restore the data
problem is, the array is 200gb, contains literally hundreds of thousands of small image files, and were backin up over the network, to back this up would take around 19-20 hours, the restore equally as long, the thought terrifies me to be honest
21 REPLIES
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

If it is a win2k sp3 server and the disk is dynamic you are all good.

1)launch your acu
2)select the array you wish to add drives to
3)select the expand option and add the new drives
4)save your configuration
5)click on the logical drive for that array
6)click the extend option
7)save your confiugration
8)download diskpart from MS website
9)goto dos, launch diskpart
10)type list disk
11)type select disk # (where # is the # of the disk you wish to extend)
12)type list volume
13)type select volume # (where # is the # of the volume you wish to extend)
14) type extend

after a few seconds to a few minutes it will finish and tell you so. Type exit to close diskpart and type exit again to exit dos.

voila! you have now extended your volume with zero downtime.

as always I would perform a backup first as best practice. I have used this same method several times without any hitch (just used it this morning a ML530 going from 18GB drives on RAID1 to 72Gb drives).
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

ahhh...I meant to say if the disk NOT dynamic. sorry

it must be basic.

sorry again
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

have u actually done this??
the disk is basic, so will this work? what about the error message from the ACU when tryin to expand an existing logical drive? saying that data loss could occur?
and is runnin diskpart from a dos box enough? or really from dos
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

and with regards to points 5,6,7, this is from within the windows disk management gui?
thanks for your help
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

1)have I done this, yes many times even did it about 9am this morning.
2)basic disk, yes, see my second post.
3)ACU warns you yes, in later releases it actually tells you that this disk must be basic and the server win2k sp3 or later. I have included a screen shot of the later release warning so you can see for yourself.
4)diskpart, yes just run it from a dos prompt.
5) points 5,6,7 are all meant to be done via the Array Configuration utility.
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

cool, thanks a lot, will give it a go
will be going onsite with an SDLT, in order that we get a good quick backup, downtime must be kept at an absolute minimum, so hopefully we can do this without too many problems
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

On the server I expanded this morning it is a production SQL2000 box. Not even the DBA was aware what I had done, until I sent the email letting him now he now had more free space ;)

good luck
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

ok, are you aware of any problems of adding more than 1 disk to the array? im plannin on adding two disks, and a few people have said (without givin a real reason), that you should add one disk at a time, wait for reinitialisation of the whole array, then add the 2nd disk
the machine is fairly new (ML530 g1, with a 5300 raid controller)
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

Best practice is to do one disk at a time and wait. I personally have never tried multiples at once on a RAID 5 set so I cannot give you any real world advice on that. I can tell you the 5300 is an amazingly fast controller and it should not take to long. On my ML530 I have a 5304-128 array controller and when I swapped the 18.2GB for the 72GB drives it took about 20 minutes per drive to rebuild.

good luck.

mike B.
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

doing this just now
just expanded the array, waiting for the thing to reinitialise before itll let me do the the logical disk expansion, just how long does this take normally?
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

not sure off hand. I will test it with a box on my desk and let you know.
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

so how did you fair on this?
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

tonight is the big night
worked on my test system (adding one disk (72gb) to a 3x72gb raid5 set, did some strange things, took a while (about 1 hr) to initialise the newly expanded array, although it was available during this time. seemed to go ok
tonight will do it on the live system, have been busy backing up the 180gb worth of fotos (its a database server for a traffic tunnel, thers a picture per vehicl from all traffic from the last year), around 4200000 files.... even with SDLT hung directly on the server, the backup is taking a while...
but thanks for your help, hopefully itll go fine, will let u know
Mike Bollman_1
Respected Contributor

Re: expanding RAID5 set

graeme just wondering how this went?
Matt Lawrence
Occasional Advisor

Re: expanding RAID5 set

I am about to add a disk to a RAID5 set, basic. I would sure like to know if this worked. Any follow-up information on this would be greatly appreciated.

Matt L.
graeme_15
Occasional Visitor

Re: expanding RAID5 set

yes,
was possible. a few things to watch out for though
take a backup first, obviously
the steps the other guy outlined were fine, just follow them, i.e expand the array, then the logical drive, then use diskpart to allow windows to see the bigger disk
however!! depending on what your adding to the system, this can take a long time
we added 4x72gb to an existing array, it took 3 days for the array to expand (was always accessible during this time though(, i think HP say expect 15min per gig
expanding logical disk was quicker.
watch out, the maximum size of an expanded logical drive which the ACU can handle is 255gb, our logical drive was already 200gb, so we could only add another 55gb to it..
apart from the that, no issues, no data loss, and no downtime
Prashant (I am Back)
Honored Contributor

Re: expanding RAID5 set

graeme welsh
Occasional Advisor

Re: expanding RAID5 set

Prashant

what interesting information is contained in this link?
is it possible to expand a logical drive greater than 255gb with the latest version of ACU?

Mark Johnston_1
Occasional Visitor

Re: expanding RAID5 set

I am also having this problem with the 255 GB limit on an expanded array. I can't add any more space to the logical drive.

I just spoke to Conpaq Support and they informed me that this 255 GB limit has something to do with the number of cylinders and sectors on a disk. This 255GB is the MAX size allowed even with the most recent version of HP Array Configuration Utility. He said that there is a Beta version being tested now that will get around this restriction and allow up to 2 TB of space, but it's not available from HP yet but he suggested I try to search for it from one of HP's beta testers.

Does anyone have this Beta version of the Array Configuration Utility I can use?

Thanks.
Matt Lawrence
Occasional Advisor

Re: expanding RAID5 set

graeme,

I have added the new drive to the array. The Compaq Array Configuration Utility now shows Array A with Logical Drive 1 and my new disk as Unused space. When I highlight Logical Drive 1 and choose Extend it gives me the warning:

"You have requested to perform extension on this logical drive. Extension is not currently supported on Windows 2000. If the operating system for this logical drive is Windows 2000, please do not attempt to use this feature, as data-loss could occur."

Are you telling me that I should choose yes here to allow it to extend and it will work? Or at least it worked for you? This step has me worried.

Thanks,

Matt L.
graeme welsh
Occasional Advisor

Re: expanding RAID5 set

yep, that was the same error message i received, apparently its been removed with later versions of the ACU, (HP-ACU-XE, web based version), and so long as the disks are NOT dynamic this will work, no problem, itll take a bit of time, but your array is always accessible. after the araay is expanded, expand the drive, then use diskpart to allow windows see the new space