Re: maximum size

On Tuesday September 27, lfarkas@bppiac.hu wrote:

Neil Brown wrote:

quoted

On Tuesday September 27, lfarkas@bppiac.hu wrote:

quoted

hi,
i'd been already asked, but don't get any answer. what is the maximum 
size of a raid5 and raid5 partition in kerenel 2.6? i try to find the 
answer but found only kernel 2.4 info.
thanks in advance.

Providing you are using either 64bit hardware, or the 'LBD' (large
block device) config, then raid5 arrays can be up to 2^64 -
i.e. enormous - no practical limit.

huu, i don't know. we use 3ware 7506 controller. on it onw homepage it 
said:
---------------------------
Supports up to 12 drives with a single PCI card enabling up to 3.6 
terabytes of storage (dependent on drive capacity, 2TB per array maximum)
---------------------------
but it's all about the hardware raid5. so it's native hardware raid5 
can't be larger than 2TB.

Quite possibly.  I was talking about 'md' software raid.  It don't not
have a 2TB limit in 2.6

quoted

I don't know what you mean by 'raid5 partition'.  If you mean like a
regular partition of a device, then the partition can be nearly as bit
as the array....

suppose i create the raid device with:
mdadm --create /dev/md0--level=5 --raid-devices=8 --spare-devices=1 
/dev/sd[abcdefgh]1
then what is the maximum size for /dev/md0?
(or more precisely after a mkfs.ext3 /dev/md0).

The /dev/sdX1 cannot be larger than 2TB.  The /dev/md0 can be as big
as you like.  The filesystem can be as big as your filesystem allows.
I don't think ext3 can exceed 2 TB (I could be wrong).  Other
filesystems (reiser, xfs) can certainly use whatever you can through
at them.

NeilBrown