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Bigger SAS drives in raid 10 - ML370 w/ P600

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it helpdesk_8
Occasional Visitor

Bigger SAS drives in raid 10 - ML370 w/ P600

Hi guys,

Our company has just purchased bigger Sas drives for our ML370 with a Smart Array P600 and Windows Server 2003 SP1. I'm not sure on firmware/ BIOS versions at the moment, since I'm not a regular to the site and have never rebooted the server.
Currently, all drives are 73.4GB, and we're replacing them with 146GB drives. I want to do with with as little downtime as possible, since it's a live database server. So I just need to confirm how to go about this.

- Replace drives 1 by 1, letting the mirror rebuild between each swap.
- Once all drives are in, extend the logical partition to fill the extra space and reboot so Windows can see it.

In theory this sounds about right, but I'm not familiar with ACU at all. Are there any "gotchas" I should know about (like the Raid 0 part of things), or am I even on the right track?
If someone can explain the process in greater detail so I can give an estimate to management on downtime and completion, that would be great. Of course, tape backups are being made and will be verified before the process begins.
9 REPLIES
~sesh
Esteemed Contributor
Solution

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

The rebuild process once the new hard drive is installed is automated, ACU is not required for it.

Once the array rebuilds, only then you will need to use ACU to extend the logical drive to fill up the remaining space. The ACU can be accessed from within Windows also, which presents an easy to use intuitive interface.

The RAID level doesn't matter, but it should be something that supports redundancy. If you have RAID 1, 5, 6, 10 - then you can remove the old drive & swap it with the new (bigger) drive.

RAID 0 doesn't support redundancy, so removing a drive will cause the array to be broken.
it helpdesk_8
Occasional Visitor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

Ok, cool.

Being a 1+0 array should be fine then. I was told by another server tech that I work with that I'd need to blow away the array, build it with the new drives and restore the backup. I didn't think that would be necessary on an array with mirroring, as long as it can be extended once the new drives are all installed.

Thanks for the info.
KarloChacon
Honored Contributor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

hi

who says you need downtime to do this process that is a completely online process
I mean while your server is up and running

P600 controller features:
* Online Capacity Expansion
* Online RAID Level Migration
* Online Stripe Size Migration
* Online Spares (Global)
* User Selectable Expand and Rebuild Priority

so your process is going to be: Online Capacity Expansion
which is adding new HDDs to an existing array or replacing HDDs with larger drives

http://h18004.www1.hp.com/products/quickspecs/12247_na/12247_na.html

and yes your procedure is right.

*** first update firmware for the controller and existing HDDs and backup very important

yes while Windows is working replace one by one. after the procedure is complete your going to get unused space in the (the difference depending on the RAID level you are using) so you can see and extend that unused space using diskpart or a third party partition software.


Regards
Didn't your momma teach you to say thanks!
it helpdesk_8
Occasional Visitor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

Thanks, Karlo,

That's the exact answer I was looking for.

10 points to you, sir!
KarloChacon
Honored Contributor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

thanks

something else I forgot to mention is the priority for the rebuild process what means the resources the controller is going to use to work rebuilding the HDDs, check this (the one that is important for us is changing the priority for rebuilding)

Controller settings:

The default controller settings that ACU provides are adequate for many purposes. When necessary, however, you can use the Controller Settings task to:

â ¢ Alter the priority that the system gives to an array expansion or rebuild
â ¢ Disable the array accelerator (if one is present)
â ¢ Change the ratio of read cache to write cache (if the controller has battery-backed cache)

To change the controller settings:

1. Click Controller Settings, and then click Begin.

The next two screens enable you to change the settings for the expand priority and the rebuild priority. These settings determine how much importance you want an array expansion or rebuild to have relative to normal I/O operations.

â ¢ With low priority, the expansion or rebuild takes place only when the array controller is not busy handling normal I/O requests. This setting has minimal effect on normal I/O operations.
However, there is an increased risk that data will be lost if another physical drive fails while the rebuild or expansion is in progress.

â ¢ With high priority, the rebuild or expansion occurs at the expense of normal I/O operations.
Although system performance is affected, this setting provides better data protection because the array is vulnerable to additional drive failures for a shorter time.

â ¢ At the medium priority setting, expansion or rebuild occurs for half of the time, and normal I/O requests are handled during the rest of the time.

2. Set the expand priority to high, medium, or low, and then click Next.

3. Set the rebuild priority, and then click Next.

If the controller has an array accelerator, a screen now appears that gives you the option of disabling it for particular logical drives.

NOTE: Disabling the array accelerator for a logical drive reserves use of the accelerator cache for other logical drives on the array. This feature is useful if you want the other logical drives to have the maximum possible performance (for example, if the logical drives contain database information).

4. Select the logical drives for which the array accelerator should be disabled, and then click Next.
If the controller has a battery-backed cache, a screen now appears that enables you to change the read/write cache ratio. This ratio determines the amount of memory allocated to read and write operations. Different types of applications have different optimum ratios. You can change the ratio only if the controller has a battery-backed cache (only battery-backed cache can be used for write
cache) and if there are logical drives configured on the controller.

5. Select the ratio that you want the controller to use, and then click Next.

6. Click Finish to accept the changes.

7. Click Save to apply the changes to the system, and then click OK on the confirmation alert.

source, page 31
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00729544/c00729544.pdf


regards

Didn't your momma teach you to say thanks!
dms_1
Trusted Contributor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

Hi,

I just want to add something to one of Karlo`s posts.

After expanding the array and the logical drive you cannot use diskpart.exe (included in Windows) to extend your system partiotion (C:)

There another ways to do that, for example:

1. use Symantec volume manager - you boot from DOS CD and run that software

2. use a linux bootable CD named ParteD - look on google, you can download the ISO, boot from it, it is all nice GUI

Hope this helps.


CLEB
Valued Contributor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

Hi

Just wanted to add that Parted does not work with NTFS volumes.
e4services
Honored Contributor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

My thoughts exactly as I read. This may be why the other IT guy said to back up and restore. If you are carrying a single RAID volume and a single OS logical "C:" drive holding both your OS and database, this would be your solution (backup and restore). As stated above, you will not be able to enlarge your system partition and you would have to create another partition with the additional free space and use it in what ever manor works for your space requirements.
If it was me, keeping in mind the time requirements for the system to rebuild each 73GB drive (not fast), then the time to extend the RAID logical, then time to create and format the new OS partition, I would simply ADD the 2 new 146GB, leaving the 73GB's running the OS. Create a new mirror and logical on the new drive and place and format a new OS partition of 140GB. Then you can relocate your DB to them and get them off the OS drive.
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Pamela Dilworth
Occasional Visitor

Re: Bigger SAS drives in raid 10 - ML370 w/ P600

I am about to embark similarly. Want to swap bigger Drives in Raid 1 - ML350, Smart Array 641 and Netware 6.5SP6.

Is there anything extra I need to watch out for - or can I go ahead and follow the above procedures?