Increasing HP RAID array size

I look after a HP ML350 G6.

It was built with 7 x 146GB 2.5" 10K drives configured as RAID1 + RAID10 + shared hot spare. It's getting to the point where it needs some additional storage.

As it happens it has just had two drives replaced under warranty, both from of the RAID10 array, and the replacement drives are 300GB rather than 146GB.

I was thinking about replacing the other two RAID10 drives with 300GB versions plus a 300GB hot spare.

The plan would then be to expand the array to use the new space, and then either expand the existing partition or add a new one.

Does this seem possible/sensible? Is there anything nasty lurking in the background I should be aware of?

If you have cache you should be able to swap one drive, let it rebuild, swap the last drive, let it rebuild, then expand.

But it would be a lot less load on the disks to wipe, re-create using 4x300 and then restore.

bremen1874 said:

Does this seem possible/sensible? Is there anything nasty lurking in the background I should be aware of?

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This sounds fine, although as with anything like this - make sure you have a backup first.

nutcase_1uk said:

If you have cache you should be able to swap one drive, let it rebuild, swap the last drive, let it rebuild, then expand.

Click to expand...

IIRC it's a requirement to have the Battery Backup unit in order to do any online array expansion rather than a specific cache requirement (so worth checking this first - although a used BBU and 512Mb Cache unit was only around £20 last time I checked - assuming it is the common SmartArray P400 or P400i RAID card)

nutcase_1uk said:

But it would be a lot less load on the disks to wipe, re-create using 4x300 and then restore.

Click to expand...

In RAID10 this isn't an issue, as literally all it is rebuilding is a single drive, it doesn't take much time (As opposed to a RAID5 or 6 rebuild that involves all disks to calculate parity, placing huge load, and has a long rebuild time - increasing chance of further failure)

Re the battery, thats probably why I couldnt expand the array on my Microserver. I did the disks swaps and let them rebuild but I had to add a new logical disk to make use of the extra space.

It has a P410i with BBU so I should be okay.

I think I'll get the drives ordered and give it a try.

Armageus said:

In RAID10 this isn't an issue, as literally all it is rebuilding is a single drive, it doesn't take much time (As opposed to a RAID5 or 6 rebuild that involves all disks to calculate parity, placing huge load, and has a long rebuild time - increasing chance of further failure)

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It's more the expansion that hits the disks - you're right, a straightforward disk replacement on a non-parity RAID array doesn't take much effort

Okay, I've replaced the 146GB drives with the 300GB versions and have added a 300 GB hot spare.

I've now got:

• RAID1: 2 x 146GB + dedicated hot spare
• RAID10: 4 x 300GB + dedicated hot spare

I've now realised that while I was 100% sure there was a battery installed there actually isn't (or it's reporting as missing because it's dead). I'm assuming this is blocking the options to expand the array?

The server (ML350 G6) has a P410i with 256MB cache.

I've got a spare P410 with 512MB and battery. From what I can tell the cache module and battery should fit the ML350. I need to actually get a physical look inside the server, but it looks likely.

I may just go down the safe route and create a new logical volume on the now spare drive space, but expanding the volume would be more elegant.

Any thoughts? TBH I'm much more comfortable with Dell servers.

99% sure that the cache module will fit.

Worse case if it doesn't though, you could fit the spare card and connect the SAS cables to that (it should just detect and want to import the arrays when you power up)

It should 'just work'
I replaced a P410 with a P420 and it booted straight up and detected the drives no problem.

I installed my cache module and battery. The server now has 512MB of cache instead of 256MB but is reporting the battery as failed.

The battery has been on the shelf for quite a while. I was hoping that a few hours on charge might bring it back to life but no luck so far. A remote reboot made no difference.

I may have to go shopping for a battery.

http://opensource.wrenhill.com/?p=63

If ya feel like doing it yourself.

GDL said:

http://opensource.wrenhill.com/?p=63

If ya feel like doing it yourself.

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I did it, works brilliantly.

I found that guide when I searching for a new battery yesterday. If it was my server and my money I'd be very tempted. Luckily the batteries don't appear to be too expensive to buy new.

I've had Dell servers where you needed to power the server completely down and restart from cold to get a previously discharged battery to be recognised. Any chance the HPs are the same?

The replacement battery I had ordered finally arrived. Surprisingly difficult to find new from a reputable supplier without spending over the odds.

After it was installed and had fully charged the options to expand the array appeared and the job is now done.

bremen1874 said:

The replacement battery I had ordered finally arrived. Surprisingly difficult to find new from a reputable supplier without spending over the odds.

After it was installed and had fully charged the options to expand the array appeared and the job is now done.

Click to expand...

Pleased you got this sorted