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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?

Thanks

ewwhite
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JLe
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  • 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 07 '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 07 '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 07 '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 07 '12 at 19:51
  • (ran out of comment space in the previous comment) I am going to assume that you make and test a backup before doing this. Which means it is probably faster to restore the backup to a newly configured and formatted RAID then you slowly convert an existing RAID. This al depends on your hardware, but my experience with live conversion of RAID arrays if that it is often a very slow process. – Hennes Jul 07 '12 at 19:51
  • Ah oh, I wasn't clear enough in my first post. I will edit that. I forgot to write that there is only one drive at the moment (which isn't RAID-0, but HP ACU calls it that). – JLe Jul 07 '12 at 19:52
  • Ugh. I have a Dell laptop which came with a 'single disk RAID'. After some research I understand what Dell wanted to say (BIOS set to RAID enable and a drive which is very much non-RAID), but it still sounds wrong to me. A single disk is never RAID unless it is RAID across partitions on that drive. And there are many reasons not to do that. OK, I ranted. Back to your question. You have all data on a single drive. Adding a second drive as mirror makes sense. I still recommend making backups first. And TEST those backups. – Hennes Jul 07 '12 at 19:57
  • I'm currently running Ghost to make a copy. Not quite sure about how to test it though... Anyway, I'll start HP Offline ACU when that's complete and see what is says. But in every thread I found on the internet it says that I need a battery to be able to transform it into a RAID-1, and everyone except seems to have one. So a definite answer if it is possible without battery would easy my mind. – JLe Jul 07 '12 at 20:02
  • If power fails while it is migrating the data on the RAID arrays and you have no BBU then you are likely to end up with a broken array. This is not acceptable in an enterprise environment. So if I was HP I would disable that option when there is no battery present. (Warnings would also work, but most people seem to ignore then). But since you now have a ghost backup: go for it. In the worst case you need to restore that backup. – Hennes Jul 07 '12 at 20:07
  • I dont see the reason why this should not work. Maybe only because some very old firmware. The raid 0 to 1 upgrade from a single drive was always OK on different raid systems – Andrew Smith Jul 07 '12 at 20:29
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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 07 '12 at 20:33

1 Answers1

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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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ewwhite
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