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Can't Expand Array on HP P222 on Gen8


ChronoSphere
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I've installed an HP P222 with a 512mb FBWC w/ a supercap battery.I was able to successfully migrate my 2x3TB RAID1 array from the B120i to the HP222 no problem.

 

Now for the life of me I can't find any options to expand the array (add disks) so then I can subsequently change the raid level. I've looked at the SSA (Smart Storage Administrator) and I don't have an option for expanding the array. Spent the past 1/2 hour looking and no dice. Help?

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So I was able (I think!) to expand the array using the SSA CLI interface. Its now has a status of transforming, and is now listed as a RAID1+0 instead of a RAID1 array. Strange that I wasn't able to find any UI options to do the same. 

 

Once this is done I'll attempt to change the RAID level to 5. I have all my data backed up just in case. The boot volume is a paid of SSD's on RAID1 controlled by the B120i, not the P222.

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So I was able (I think!) to expand the array using the SSA CLI interface. Its now has a status of transforming, and is now listed as a RAID1+0 instead of a RAID1 array. Strange that I wasn't able to find any UI options to do the same. 

 

Once this is done I'll attempt to change the RAID level to 5. I have all my data backed up just in case. The boot volume is a paid of SSD's on RAID1 controlled by the B120i, not the P222.

Man, I would be really surprised if this worked. Didn't know it was possible to change from one RAID type to another. I guess it sort of makes sense that you can go from 10 to 5 because 5 gives you more disk space, but it must introduce terrible fragmentation! (I assume that going from 10 to 5 means you are going from 2 stripes to 3, leaving that 3rd stripe empty on every track).

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Man, I would be really surprised if this worked. Didn't know it was possible to change from one RAID type to another. I guess it sort of makes sense that you can go from 10 to 5 because 5 gives you more disk space, but it must introduce terrible fragmentation! (I assume that going from 10 to 5 means you are going from 2 stripes to 3, leaving that 3rd stripe empty on every track).

 

Some forms of what is known as RAID-level migration do work, and this is not uncommon on enterprise RAID controllers, since needs change over time..  In fact, taken from the Gen8 Smart Array Data Sheet:

 

The addition of HP SSA can help you configure array controllers, expand an existing array configuration by adding drives,

or reconfigure an array by extending volume sizes. You can also make use of enterprise-class features such as online

RAID-level migration and online capacity expansion to make alterations to the storage system without disrupting the current workload.

 

Dell PERC controllers also have similar features.  With the Smart Array controllers, some of these functions can actually be done without taking the system offline, though I'd never do it without a good backup.  It's not uncommon for someone to want to take a RAID 1 to RAID 10, a RAID 5 to RAID 6, or in some cases more complex setups (like in large enterprise, a RAID-50 to RAID-60).

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Did you try the off line SSA?

 

No I didn't - my understanding was that you can migrate raid levels while online. I may have been mistaken though - but the fact that I was able to initate it through the CLI makes me wonder if it was simply left out of the UI. I found plenty of screenshots online on how to do the raid migration via the older ACU, while how-to's for the SSA was less common.

 

Man, I would be really surprised if this worked. Didn't know it was possible to change from one RAID type to another. I guess it sort of makes sense that you can go from 10 to 5 because 5 gives you more disk space, but it must introduce terrible fragmentation! (I assume that going from 10 to 5 means you are going from 2 stripes to 3, leaving that 3rd stripe empty on every track).

 

Yeah this was my original intent - I actually had a couple of posts with Schoondoggy a few months ago to confirm if this was possible - as I didn't have the cash at the time to outlay for the server+ram+4 disks+controller card. I just got a pair of 3TB reds in a raid 1, and a pair of 120gb ssd's for boot in raid 1, all on the b120i controller.

 

Now the new card came in, 2 new disks, migrated existing disk to new array, now its expanding, and then the next step is to migrate the raid level. Its been running since last night and now its at 45% complete (i have 1.5TB of data on the array). I wonder if it would have just been faster to wipe the disks, build the array fresh as a RAID 5, then copy the data back onto the array from backup. Oh well :)

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I believe the old ACU utility had these features in the GUI, but it looks like SSA may just support these from the command line. I will check the next time I am working with SSA.

It probably would be faster to setup a new RAID5 and move the data. There should be a setting to control performance vs rebuild priority. The feature is more of a hands off enterprise function.  

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Some forms of what is known as RAID-level migration do work, and this is not uncommon on enterprise RAID controllers, since needs change over time..  In fact, taken from the Gen8 Smart Array Data Sheet:

 

The addition of HP SSA can help you configure array controllers, expand an existing array configuration by adding drives,

or reconfigure an array by extending volume sizes. You can also make use of enterprise-class features such as online

RAID-level migration and online capacity expansion to make alterations to the storage system without disrupting the current workload.

 

Dell PERC controllers also have similar features.  With the Smart Array controllers, some of these functions can actually be done without taking the system offline, though I'd never do it without a good backup.  It's not uncommon for someone to want to take a RAID 1 to RAID 10, a RAID 5 to RAID 6, or in some cases more complex setups (like in large enterprise, a RAID-50 to RAID-60).

Going from 1 to 10, or 5 to 50, or 5 to 6 -- that is all completely feasible and makes sense. Adding disks to an array to extend it -- also makes sense. Converting from 10 to 5? I'm not so sure about that, and that's why I am keen to see what the OP discovers.

Edited by rotor
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Going from 1 to 10, or 5 to 50, or 5 to 6 -- that is all completely feasible and makes sense. Adding disks to an array to extend it -- also makes sense. Converting from 10 to 5? I'm not so sure about that, and that's why I am keen to see what the OP discovers.

You can change RAID level and even the stripe size whilst online. Online RAID migrations are a fairly standard feature for higher end RAID controllers. You need a FBWC or BBWC to actually do the migration though as the controller needs temporary space whilst it is rewriting everything and it also needs to keep track of the current progress. Failure of the FBWC/BBWC module is likely to cause you to lose all your data so backups are essential.
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You can change RAID level and even the stripe size whilst online. Online RAID migrations are a fairly standard feature for higher end RAID controllers. You need a FBWC or BBWC to actually do the migration though as the controller needs temporary space whilst it is rewriting everything and it also needs to keep track of the current progress. Failure of the FBWC/BBWC module is likely to cause you to lose all your data so backups are essential.

 

Funny you say higher end raid controllers - doesn't HP position the p222 as its entry level?

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