I have an HP ML350 G6 with a P410i zero memory RAID controller. As far as I can understand that means I can't expand a current single drive "RAID-0" configuration to a RAID-1 using the HP Offline ACU without installing memory and BBWC. Is that correct?

What makes me think about this is the fact that expanding RAID-0 to RAID-1 should be pretty similar to replacing a failed drive in an already existing RAID-1? So then why can't I expand without memory and BBWC?

Is my best option otherwise to (i) use Ghost to capture the disk, create a new RAID-1 with the existing drive and a new one or (ii) buy memory+BBWC and do it online?


  • I fail to see the link between changing the array from RAID-0 (mirror) to RAID-1 (stripe) and the replacing of an external drive. If you assume it is because they just need to one a single new drive then you ignore the capabilities of the hardware. It most like does smart stuff such as placing each even numbered sectors on one drive, and each odd numbered sector on the other. – Hennes Jul 7 '12 at 19:36
  • I might be very wrong, but I basically thought that changing from RAID-0 to RAID-1 only required the controller to copy all the data on the first drive to the new one, which I guessed was what it would do if I had to replace a drive in a RAID-1. – JLe Jul 7 '12 at 19:40
  • I reversed mirror and stripe. Lets retry: You currently have RAID 0, which is block level striping. Your RAID array has a capacity which is the sum of two drives. (E.g. two 1TB drives in a stripe would yield a very fast 2TB drive). Data is distributed over both drives and if one of them fails you loose all data. You want to change that to RAID 1 (mirroring without parity or striping). That would result in a 1TB disk which will keep working even if one of the drives dies. That sounds like a non trivial operation for which I would make a backup of all data before attempting it. – Hennes Jul 7 '12 at 19:49
  • And how many drives you have now? With two drives, you put another 2 and setup RAID 10 – Andrew Smith Jul 7 '12 at 19:51
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    @AndrewSmith "And how many drives you have now? With two drives, you put another 2 and setup RAID 10" - That's wrong. You'd have a RAID 0+1 in that instance, not a 1+0. There are some important differences and 0+1 should be avoided whenever possible. – MDMarra Jul 7 '12 at 20:33

Array transformations are possible, but you need to have a BBWC or FBWC unit in place to do so (offline OR online). You may as well get cache memory and a battery since write performance is very poor without them.

See the HP Smart Array Configuration Utility manual.

Also see: RAID5 on SmartArray P410i online resize

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