Smart Array HBA's: growing a logicaldrive onto larger disks?

[anthony11]

Using any Smart Array HBA, say the onboard p410i:  say I have a RAID 1+0 striped mirror logicaldrive that contains 4x 73GB disks (146GB volume).

Is it possible to replace one disk in each mirror pair with a larger disk, say a 300GB, resync, replace the other side with a 300GB, sync, then grow the logicaldrive to fill the disk, ie. creating a 600GB volume in this case?  The filesytem would of course then need to be grown to use the new space.

This can be done with Solaris SVM, and it's a breeze with ZFS, but I can't find any reference that describes the process for HP SA HBA's.

[Thomas Martin]

Hello,

you can replace one drive by the other. Replace one, wait still rebuild is done. Replace the next. After all drive have been replaced you need access to the Array Configuration Utility. For Solaris there's a CLI Version available. Have a good backup before you change something with the Utility. If you can shut down the server you can use SmartStart CD to boot the server. There is a GUI to manage the SmartArrayController. You can expand each logical drive. Be carefull with the Boot LUN. All partitions on each logical drive arent expanded. You can see free space after the last partition. You can also create a new LogicalDrive with the free space. Your Solaris sees a new physical drive.

Thomas

[anthony11]

Actually, we're moving to RHEL.  As superior as Solaris is in several areas (*cough* *cough* ZFS *cough*) the growing trend of software being written to only build/run readily on Linux has been annoying for several years, and Oracle's actions since borging Sun have been kind of a last straw.

That's what leads me here.  Were I using Solaris on these systems, I'd just laboriously use ORCA or hpacucli to wrap each physical disk in a degenerate stripe so that BIOS and the OS could see them, then use ZFS to aggregate them into 3-way mirrors.  I could use MD in Linux-land, but would still need to set up the stupid single-disk stripes, and the MD stuff appears to be fairly clumsy to administer, and what I read about LVM indicates that it really isn't usable for mirroring.  Plus I'm told that HP HBA's actually manage the disk-bay lights to indicate a disk when it fails, which has a lot of appeal.  Every time in the past I've tried to work with remote hands to swap a bad disk, my stomach has been in knots out of fear that they'll pull the wrong idsk.

I haven't messed with ACU.  AFAICT it hooks into something called SMH, which appears to be some sort of system management tool with an embedded web interface and password authentication -- I haven't figured out how to set that up or restrict access from the network at large, so right now I'm limited to the bizarre ORCA CLI, and hpacucli.

Chances are that I'll never care about doing this on the boot volume, but your caution is prudent.  I havent encountered a SmartStart disc/ISO, but note that our systems are managed remotely.  Some won't have a physical optical drive, and getting someone to burn/insert a disc into one often wouldn't be practical.  iLO's remote device redirection is really slow even domestically -- I can't imagine how bad it would be over a trans-oceanic connection.

Since these systems have at least 8 drive bays (though not 24 like the x4270m2, alas), data will generally be on a RAID 1+0 logicaldevice separate from the boot volume.  I haven't done anything with having multiple partitions on data logicaldevices, nor as HP describes them, more than one logicaldrive per "array" on the SA HBA, partly because the ORCA and hpacucli interfaces don't AFAIK do that, and partly because I am unlikely to have a need to do so.

Thus, in the described scenario, I'd be wanting to expand the existing logicaldrive to fill the additional space on each component disk -- adding  a second logicaldrive made from that space wouldn't meet the need of having to expand the filesystem to fit.

So, if I figure out how to get ACU going, I should see a facility therein to expand existing logicaldrives to fill their physicaldrives?  Do you know if this is / isn't possible in hpacucli?  HP's documentation for the latter is skimpy, and HP's support people, after seveal rounds of not understanding what I was trying to do, told me that it couldn't be done at all.  I haven't seen reliable answers from them on other issues, so I didn't want to necessarily believe that.

[gregersenj]

Yes

You can do that.

You will find this document most helpful:

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00687518/c00687518.pdf

Beware:

The P410 require a BBWC to do changes to the Array and Logical drives:

http://h18000.www1.hp.com/products/quickspecs/13201_div/13201_div.html#Standard Features.

Importen understadning of terms:

Expand Array = Add more physical disks to the Array.

Extend Logical Drive = Make a logical drive larger. You will need free space on the Array.

Array = a groupe of disks, that work togther. - RAID level not defined here!

Logical drive = That's what you create within an Array, and is presentet to the OS as "physical" drives.

RAID level is defined with the logical drive.

You can have multible logical drives in an Array, even with different RAID levels.

Basic configuration, can be done offline, using the ORCA during post.

You can create Arrays, with only 1 Logical drive, that use all space on the Array.

It can create multible arrays, and assing spares / global spares.

For the advanced stuff, you will need to use the ACU.  GUI or CLI.

ACU can be used on-line and off-line.

Please read the Technology brief (first link).

Let me know if you need futher explanation.

PS. I have zero knowledge on Solaris, and very little on Linux.

BR

/jag

[anthony11]

Thanks -- I've seen that document, and its failure to address the scenario I describe is what prompted me to ask here.  It describes adding disks to an "array" or logicaldrive, but not swapping out existing disks for larger disks.

All P410i's that we have or will get in the future have BBWC512MB.  For larger configurations we'll buy new P812's which I believe come with flash instead.  For $1299 list they should wash my car and change my son's diaper too.

The documents made me aware of HP's use of the term "array" as well as their odd use of "strip size" vs "stripe size", and of the theoretical possibility of having multiple logicaldrives within an "array".  I can't see that we'll have any reason to do the latter -- if for some reason we feel the need to build multiple filesystems on a given array/logicaldrive, we'll use LVM (sigh -- I REALLY miss ZFS), but I hope we can avoid that.  The use of ORCA during post is painful at best:  the syntax is almost completely undocumented and has buggy and dangerous behavior:  see below where "detail" is interpreted as "delete".  The inability to cut/paste commands because the thing can't accept characters that fast also limits the utility of this interface.  I regard it as only to be endured to configure the boot volume before OS installation.  The need to reboot the system to get to it also severely limits its viability.  I'm not entirely sure if one can even create multiple logicaldrives per array using this interface, or if one has to use hpacucli or (shudder) ACU.

CLI> controller create type=logicaldrive raid=1 drives=4,5 spare=6,7
CLI> logicaldrive * show
Logical Drive # 1,RAID 1+0, 68.3 GB,Status OK                                 
Logical Drive # 2,RAID 1+0, 279.4 GB,Status OK                                
CLI> logicaldrive 2 detail
Are you sure? (y/n):  
CLI> logicaldrive * show