PE 2900 raid 5/i

Question

Hello,

We have a Power Edge 2900 with raid 5 system. Running low on space and want to change out the 3 73gb drives with one spare to 146gb drives with one spare. I have read that you can do this one drive at a time but how do you add the NEW unused space into the existing virtual disk to be used once all drives come back on line.

Current system is

windows 2003 sbs sp2

raid 5 on perc 5/I with one virtual drive partitioned into 2 drives C: and D:

Thank you in advance,

theflash1932 · Accepted Answer

You can't. That is not how the PERC's Online Capacity Expansion works. If you swap them out one at a time like that, the only thing you can do with the new space is create a new (second) RAID 5 array across the disks. This will show as a separate "disk" to the OS, so it cannot be used to merge with existing partitions.

You may read about an operation used to do this - called a retag - but this is a RECOVERY operation and was never intended to be used on an array of a different size (to expand). Best case scenario, it will appear to work, then crash days, weeks, or months later. If you don't mind the downtime or recovering from backup when it crashes, then this is a "shortcut".

If you must have the space accessible to existing partitions (merging, etc.), then you need to backup, remove small disks, insert large disks, create new/larger RAID 5, restore. If you are ok having the new space appear to the OS as a new/separate "disk", then swap them out one by one.

The way Online Capacity Expansion works, is you can expand an array - while online/live - by ADDING disks to the RAID array. For example, if you have a 3-disk RAID 5, you can add another disk (or more) and convert the 3-disk RAID 5 to a 4-disk RAID 5 (or however many disks you have/add).

FMikhael · Answer

Thank you for your reply, Can this be done with any third party software?

if not, I am not a big fan of restoring the OS from a backup, would there be other ways to increase the size of the drive?.

what is happening is that drive C: is getting below 10% capacity which I don't feel comfortable with

theflash1932 · Answer

'Can this be done with any third party software?'No.  When talking about hardware RAID, you are limited to the hardware implementation of the controller/disks, so there is no third-party utility that has access to the LSI/Dell firmware and API's to create such a utility - if it is even possible with the hardware. Since you haven't said, we can throw out arbitrary and theoretical numbers here - with the goal in mind that you stated - that you are dealing with a C: drive that is too small: Let's say you have the following: C:\ 12GBD:\ 124GB Now, you replace the disks with 146GB disks and create a new array with that space and create an E: partition.  Now, you have: C:\ 12GBD:\ 124GBE:\ 136GB You can now move your existing data from D: to E: and delete D:, then extend C: using a third-party utility (even a Windows Vista/7/2008 DVD will work or Dell's ExtPart): C:\ 42GBUnpartitioned: 94GBE:\ 136GB Then you can create a new partition with the Unpartitioned Space (now smaller): C:\ 42GBD:\ 94GBE:\ 136GB

theflash1932 · Answer

That should work just fine.

FMikhael · Answer

Thank you for the information, following you instruction would I be able to do the following

Change drives 1 at a time and rebuild until all drives are the new 146gb

create a new array RAID 5 and call it E using the available RAID disk space un-used by the current raid 5

copy all data from the old D to E

Delete D

extend C using third party software (partition wizard server) to consume all of the un-partitioned portion left from deleted D

then change the driver letter back on E back to D

so it would be something along the lines of

C which was 50gb to 136gb

E would be 136gb which I can change drive letter back into D in disk MGMT if need be

Sorry if some of the questions are remedial but want to make sure

Thank you in advance,

FMikhael · Answer

Thank you, Worked perfectly!

PowerEdge HDD/SCSI/RAID

PE 2900 raid 5/i

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