Two drives in RAID?

addylad · 18 Aug 2007 at 19:59

Hi,

I was thinking of two 250gb drives mirrored, but was wondering how much slower the system would be (having to do everything twice).

Also, would I notice an impact if I used striping?

Thanks!

PhillyDee · 18 Aug 2007 at 20:02

Er, what do you want out of the RAID? Peformance or redundancy?

addylad · 18 Aug 2007 at 20:15

Well, I was just wondering how much slower it is with mirroring...

So redundancy I suppose...

rpstewart · 18 Aug 2007 at 20:20

RAID1 (mirroring) is slightly slower than a single drive. Motherboard based RAID chipsets don't tend to support split reads so there's no improvement in read speed over a single drive and writes take until both drives have finished so can be a touch slower than a single disk.

Also remember that RAID1 only gives you hardware redundancy, it's not a backup. If you mistakenly delete a file it gets deleted from both disks.

addylad · 18 Aug 2007 at 20:21

Well, as long as there isn't more than a slight lag...

Any ways of making it faster? RAM or CPU?

Big.Wayne · 18 Aug 2007 at 20:42

rpstewart said:
RAID1 (mirroring) is slightly slower than a single drive

I'm not sure if that is correct, I was always under the impression that RAID-1 offered slightly better reads than a single disk (as well as offering redundancy).

Greenlizard0 · 18 Aug 2007 at 20:45

rpstewart said:
RAID1 (mirroring) is slightly slower than a single drive. Motherboard based RAID chipsets don't tend to support split reads so there's no improvement in read speed over a single drive and writes take until both drives have finished so can be a touch slower than a single disk.

Also remember that RAID1 only gives you hardware redundancy, it's not a backup. If you mistakenly delete a file it gets deleted from both disks.

Yeap, I have setup two disks in RAID one to help prevent problems with disk failure. You'll still need a backup solution e.g. an external drive.

I have found the aforementioned RAID setup slightly slower than I would expect. Would PCI RAID controller card offer better speed?

enigmo · 19 Aug 2007 at 00:00

Card-based RAID solutions would offer a dedicated processor to deal with RAID0 and 1 and to a greater extent 5 and 6 performance. Using a faster CPU should only affect the performance of software based RAID solutions.

rpstewart · 19 Aug 2007 at 11:24

A RAID card isn't going to help RAID1 performance unless you can find one which specifically support split reads on the array. It's not possible to speed up the write performance though, this is limited by the write capabilities of the drives themselves.

addylad · 19 Aug 2007 at 11:43

OK so do you think 2 x Western Digital Caviar 250GB drives mirrored would be OK.

The thing is, if I use striping, if one drive goes then I lose everything! :eek:

addylad · 19 Aug 2007 at 12:00

I suppose I could get a tiny raptor to boot from, then put all programs/files on a separate disk?

Would I have to put these in RAID, or just connect them up?

rpstewart · 19 Aug 2007 at 13:22

addylad said:
I suppose I could get a tiny raptor to boot from, then put all programs/files on a separate disk?

Would I have to put these in RAID, or just connect them up?

No, to do that you'd run them as two separate drives.

addylad · 19 Aug 2007 at 13:23

Thanks.