Huge piles of disk with LVM and/or RAID

petcherd · 12-18-2007, 02:23 PM

I want to hang a hardware array of about 9 TB of storage on a SlackWare 12 server, but I'm using SCSI to connect to the disks.

I know that SCSI will not let me allocate more than 2 TB per LUN. I also know that LVM and software RAID will let me combine a few pieces of storage into a single manageable unit. I can't seem to find what the limits of this combination might be, but I've asked that question over on the server forum.

I also heard that 64-bit Linux distros can use GPT partitioning to address larger volumes than a 32-bit OS can handle.

Can SlackWare 12 be configured to use this partitioning scheme somehow? If so, where can I find some documentation on this process?

LinuxManMikeC · 12-18-2007, 04:36 PM

LVM 2 FAQ - What is the maximum size of a single LV?

Quote:

For 2.4 based kernels, the maximum LV size is 2TB. For some older kernels, however, the limit was 1TB due to signedness problems in the block layer. Red Hat Enterprise Linux 3 Update 5 has fixes to allow the full 2TB LVs. Consult your distribution for more information in this regard.
For 32-bit CPUs on 2.6 kernels, the maximum LV size is 16TB.
For 64-bit CPUs on 2.6 kernels, the maximum LV size is 8EB. (Yes, that is a very large number.)

I don't know about software RAID.

petcherd · 12-18-2007, 04:50 PM

I just found a link to describe LVM2 limits: http://wiki.novell.com/index.php/Lin...nt#LVM2_Limits

Novell says:
Physical Extent size: Default 4MB, range from 8KB-16GB in powers of 2. There is no limit of number of extents in LVM2, therefore there is no need to adjust the extent size for large volumes

I say, "Wow!"