Large RAID Partition for a NAS

batfastad · 06-26-2008, 03:36 AM

Hi everyone

I have successfully installed a 3ware RAID card in our test server. It's set up as a RAID 6 using the 3ware BIOS RAID manager, with 5x500GB drives.

This gives me a capacity of around 1.4TB

The device is at /dev/sda and I've already played around creating a large partition on the device, but I want to make sure I get this absolutely right... before I fill it with data that will be difficult to move anywhere else.

I'm using Ubuntu Server 8.04 and I tried creating the partition with cfdisk, then formatting it as ext3 with mkfs. I can mount/umount fine and files appear to stay on there, for the moment

I tried using the graphical GParted tool but it was giving me grief - I think because I was trying to create a partition >1TB in size

However I ran the sudo fdisk -l command to list all the partition information so I could edit fstab to have the drive auto-mounted.

I get the following warning in fdisk for my RAID device at /dev/sda:

Code:

Disk /dev/sda: 1499.9GB, 1499968045056 bytes
255 heads, 63 sectors/track, 182360 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

Disk /dev/sda doesn't contain a valid partition table

Then it goes on about /dev/sdb which is the main internal boot drive, but doesn't display such a warning for my 120GB boot drive.

Eventually I will be looking to add further drives to this array to increase the capacity to 2.5TB (there's 2 spare hot-swap bays in the backplane units we bought).
The 3ware card has some sort of online capacity expansion, but I worry that I'll have to re-partition.

So basically what's the best/most future proof way to create and then format large partitions over 1-2TB?

Should I just ignore that fdisk error?

Or is that something serious that needs looking at now?

Will the ext3 file system be ok for what I'm looking for?

Thanks, B

Tinkster · 06-28-2008, 02:30 PM

That sounds odd. Now I don't have drives with that kind
of capacity floating about, but what does cfdisk think the
partitioning scheme is?

And since there's no actual data on the device - have you
tried partitioning it with fdisk?

Cheers,
Tink

batfastad · 07-06-2008, 09:04 AM

I solved this by using fdisk rather than cfdisk, now the partition is correctly appearing as /dev/sda1, and everything seems to be working ok.
I formatted the partition as ext3, and so far it's working great.

During I was mounting the device as /dev/sda which I have now found out is a no-no!

Hope this helps someone out
Cheers B

trickykid · 07-06-2008, 09:10 AM

Quote:

Originally Posted by batfastad

I solved this by using fdisk rather than cfdisk, now the partition is correctly appearing as /dev/sda1, and everything seems to be working ok.
I formatted the partition as ext3, and so far it's working great.

During I was mounting the device as /dev/sda which I have now found out is a no-no!

Hope this helps someone out
Cheers B

Yeah, think of /dev/sda or sdb without numbers as the raw disk, not partitioned or formatted. *nix will always append a number on a valid partition once it's sliced up, formatted, partitioned and a filesystem has been slapped on it.