Lawrence,
If you don't care about being 'standard', There is plenty of fluff in
the superblock to make room for more disks. I don't know how well
behaved all the tools are at using the symbolic constants though. To
Support 18 devices, you will need to allow at least 19 disks (one for
the spare/replacement), but I like using even numbers, so round it up to
20.
You'd have to change.
In linux/include/linux/raid/md_k.h
#define MAX_REAL 20
Change lines in linux/include/linux/raid/md_p.h so it reads something
like...
#define MD_SB_DESCRIPTOR_WORDS 32
#define MD_SB_DISKS 20
#define MD_SB_DISK_WORDS (MD_SB_DESCRIPTOR_WORDS * MD_SB_DISKS)
These have to be above the line with MD_SB_RESERVED_WORDS.
NOTE: the md driver primarily uses MD_SB_DISKS for the max number of
disk count. The MAX_REAL value is also used (twice), but it could have
just as well used the MD_SB_DISKS value. Oh well.
And, recompile--both the kernel and the tools.
Try it out, let us know if the tools work.
<>< Lance.
Lawrence Dickson wrote:
>
> All,
> I guess this has been asked before, but - when will the RAID
> code get past the 12 disk limit? We'd even be willing to use
> a variant - our customer wants 18 disk RAID-5 real bad.
> Larry Dickson
> Land-5 Corporation
