replacing dead disks

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lhowlett
Posts: 2
Joined: Mon Jan 02, 2012 11:39 pm

replacing dead disks

Post by lhowlett » Mon Jan 02, 2012 11:43 pm

Hi

I actually have a 5Big v1 that has 1.5TB disks in it. One of these has died and now these are no longer available from Lacie.

Does anyone know if I can use a 2TB disk in its place and the RAID will be ok? I assume it will just rebuild onto 1.5TB of the 2TB disk, but i'm curious if anyone knows?

Or, can I just purchase a new Seagate disk and mount it in the Lacie bracket?

Thanks

Mijzelf
Posts: 6196
Joined: Mon Jun 16, 2008 10:45 am

Re: replacing dead disks

Post by Mijzelf » Tue Jan 03, 2012 9:09 am

I *think* the box will accept any new disk. The 2Big2 has a script which will partition and format an empty disk, provided that the OS is still available.

When it does, it doesn't really matter which disk you plugin, as long as it's at least the same size as the others. (Beware, any 1.5TB disk is not necessarily as big as another one, on sector level. On the disk the number of sectors should be specified. Sometimes called 'LBA'. A sector is 512 bytes, so a 1.5TB disk should contain about 2929687500 sectors)

You should stay away from WD desktop disks, as they behave badly in a raid array, and the bigger ones use 'advanced format', which is a performance problem inside an (old) NAS.

Performance isn't an issue. You'd better take a cool, economical and quiet disk than some top-performer. The NAS processor is the bottleneck anyway.

lhowlett
Posts: 2
Joined: Mon Jan 02, 2012 11:39 pm

Re: replacing dead disks

Post by lhowlett » Wed Jan 04, 2012 6:59 am

Thanks. Would be interesting to try with another disk and see what happens, however i managed to find out that its covered under warranty anyway.

I guess when it gets out of warranty then it would be interesting to see what happens by replacing the disks with a more common size.

303
Posts: 3
Joined: Sat Jan 05, 2013 1:04 am

Re: replacing dead disks

Post by 303 » Sat Jan 05, 2013 1:06 am

In my experience so far, no, this is not possible. It's been the opposite, absolute failure, the RAID actually stops working when you insert the blank disk. I have tried two drives now, both the exact model (the hitachi and the barracuda) that the original 5bigs used, and neither will work. From what I am reading, we need to somehow initialize these ourselves. If anyone has any info, please share.

Mijzelf
Posts: 6196
Joined: Mon Jun 16, 2008 10:45 am

Re: replacing dead disks

Post by Mijzelf » Mon Jan 07, 2013 9:35 am

If anyone has any info, please share.
According to the initramfs from the 5Big kernel, it uses the same way to recognize a unitialized hd as other Lacie raid devices. The string "LaCieFirstBootLaCie" at offset 1536. There is a script inside which contains this code to write it:

Code: Select all

echo -n "LaCieFirstBootLaCie"  | dd if=/dev/stdin of=$l_device bs=1  seek=1536 count=20
You could try this on an empty disk, to see if the NAS accepts it. If not, you can lowlevel copy a current disk, and then write the first boot signature.
(BTW, this string is on boot exchanged by "Lacie5Big" or something like that)

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