RAID 5 issue

neGev

I have a 3ware 9650SE RAID card and 4 * 2Tb hard drives with which I'm trying to form a RAID5 array for a home-made NAS. The first time I created the array (yesterday), the total file size was 5.45Tb, as it should be.

However, seeing as it was my first experience with RAID in any capacity, I decided to familiarise myself with it a little. Now, when I try to create the exact same RAID5 array, the total file size is 2.98Tb.

I'm sure it's something simple that I've done (or not done), but if anyone could help, or point me in the right direction, that'd be great.

jpl888

neGev wrote: »

I have a 3ware 9650SE RAID card and 4 * 2Tb hard drives with which I'm trying to form a RAID5 array for a home-made NAS. The first time I created the array (yesterday), the total file size was 5.45Tb, as it should be.

However, seeing as it was my first experience with RAID in any capacity, I decided to familiarise myself with it a little. Now, when I try to create the exact same RAID5 array, the total file size is 2.98Tb.

I'm sure it's something simple that I've done (or not done), but if anyone could help, or point me in the right direction, that'd be great.

I apologise that this won't help you much. I wouldn't rely on a RAID 5 array. On at least 2 occasions in the past a corrupt piece of data has stopped an array from rebuilding after a disk failure, which meant the whole thing had to be restored from backup anyway. Great help RAID 5 is.

I think RAID 1 is safer.

In reference to your own problem perhaps you should delete the array and start again. Considering the utility will look different and have different options depending on the manufacturer it may also be a good idea to post what options there are or a screenshot if possible otherwise it will be difficult to help unless someone has prior experience of this card.

BaconZombie

You should be getting ~6TB of RAW storage presented to your OS with RAID5.

On the RAID 1 been better the RAID 5, I've no idea what jpl888 is smoking....
Plus you should have to create 2 x RAID 1 array.

Best option is to delete the array, low-level wipe the drives and start again.

jpl888

BaconZombie wrote: »

You should be getting ~6TB of RAW storage presented to your OS with RAID5.

On the RAID 1 been better the RAID 5, I've no idea what jpl888 is smoking....

Best option is to delete the array, low-level wipe the drives and start again.

You've obviously never had a RAID 5 rebuild fail on you then. I wouldn't believe it either if I hadn't seen it with my own eyes. Array wouldn't rebuild and we tried 2 different spares. Was a corrupt bit of data causing the issue. Vowed never to use it since.

Sometimes the simple solutions are the best RAID 1 every time.

neGev

Thanks for the replies, guys.

Yeah, it seems as though there's a problem with the hard drives being partially written, as any array I've tried to create is half the size it should be. A RAID 1 array claims to be 1Tb instead of 2 Tb, while a RAID 0 array claims to be 2Tb instead of 4Tb. The drives are definitely 2Tb drives, and they're recognised as such by the controller.

I'm using the 3ware BIOS manager instead of the 3ware browser manager as there's no OS installed yet. Destroying the array in the controller BIOS doesn't seem to fix the problem, so I guess formatting is the next thing to try. Would getting a bootable version of gparted or something be the best way to do it? Does it matter how the drive is formatted?

jpl888

neGev wrote: »

Thanks for the replies, guys.

Yeah, it seems as though there's a problem with the hard drives being partially written, as any array I've tried to create is half the size it should be. A RAID 1 array claims to be 1Tb instead of 2 Tb, while a RAID 0 array claims to be 2Tb instead of 4Tb. The drives are definitely 2Tb drives, and they're recognised as such by the controller.

I'm using the 3ware BIOS manager instead of the 3ware browser manager as there's no OS installed yet. Destroying the array in the controller BIOS doesn't seem to fix the problem, so I guess formatting is the next thing to try. Would getting a bootable version of gparted or something be the best way to do it? Does it matter how the drive is formatted?

Destroying the array *should* delete any and all data from the disks including partitions, or maybe creating a new array of a different size.

Those BIOS utilities often contain a low level format utility, which will definitely do it but could take a long time.

It sounds as though the other half of the space on the drives is allocated to something else perhaps another array.

Perhaps posting a screenshot of the RAID BIOS screen/configuration might reveal something.

neGev

jpl888 wrote:

It sounds as though the other half of the space on the drives is allocated to something else perhaps another array.

Yeah, this is the most logical explanation.

Tried destroying the array and it didn't make any difference; any new array I tried to create was ~1/2 the size it should be. Also tried creating four individual single-drive "arrays" (these were the correct size) and then destroying them to overwrite any information left on them. No luck with that, either.

I can't see any low-level format utility within the BIOS. Getting screenshots will be a bit tricky, but the user manual (here) has a pretty comprehensive section with screenshots about the BIOS manager in section three.

jpl888

Has the controller the latest firmware before we go any further?

jpl888

This is a silly question and I don't want to insult your intelligence but you haven't got any "hot spares" configured have you?

Just trying to get rid of the obvious stuff.

Have you got auto carving enabled?

jpl888

Could you also create a RAID 0 array and check it's the right size?

neGev

Don't worry about offending me, I need all the help I can get.

I'm at work right now, so it'll be a while before I can check or do anything.

Latest firmware: will check later, but the card is relatively new.
Hot spares: didn't actively select any, but will check this later.
Auto-carving: not enabled. Sure about this one, as I didn't know what it was, so I had to look it up.

CyberGhost

Hey neGev, never experienced a similar problem before, have you tried completely resetting all the settings? cause it looks like it's creating a RAID1 setup.

jpl888

CyberGhost wrote: »

Hey neGev, never experienced a similar problem before, have you tried completely resetting all the settings? cause it looks like it's creating a RAID1 setup.

I couldn't find an option to restore to defaults or similar in the manual but I was going to recommend that.

neGev

Will try that too and let you know how it goes.