geom raid5 module

[Olivier Cochard-Labbe]

2006/12/11, Ulf Lilleengen <lulf at stud.ntnu.no>:
> However I am interested to hear of your problems with gvinum raid5. Is it just
> stability-problems or any spesific bugs you encounter?
>

Hi Ulf,

Here is, for example, the first problem problem with geom vinum RAID5:

I have 4 disks:
- ad0: 203MB
- ad1: 101MB
- ad2: 306MB
- ad3: 101MB

If I create a raid 5 volume with these disk, can you confirme that the
theorical size should be 300MB (4 disks of the smallest drive: 100MB)
? It's the size given with graid5 and with RAID caclulator
(http://dorm.tunkeymicket.com/raidcalc/).
But with geom vinum I obtain a 611MB disk:

$ /sbin/gvinum list
4 drives:
D disk_da3              State: up	/dev/da3s1a	A: 0/101 MB (0%)
D disk_da2              State: up	/dev/da2s1a	A: 0/306 MB (0%)
D disk_da1              State: up	/dev/da1s1a	A: 0/101 MB (0%)
D disk_da0              State: up	/dev/da0s1a	A: 0/203 MB (0%)

1 volume:
V raid5                 State: up	Plexes:       1	Size:        611 MB

1 plex:
P raid5.p0           R5 State: up	Subdisks:     4	Size:        611 MB

4 subdisks:
S raid5.p0.s3           State: up	D: disk_da3     Size:        101 MB
S raid5.p0.s2           State: up	D: disk_da2     Size:        306 MB
S raid5.p0.s1           State: up	D: disk_da1     Size:        101 MB
S raid5.p0.s0           State: up	D: disk_da0     Size:        203 MB

For the second problem, you can found it on the mailing list archive:

http://lists.freebsd.org/pipermail/freebsd-geom/2006-March/001114.html
(I don't test with FreeBSD 6.2 prerelease, if I still have this second problem)

Regards,

Olivier

-- 
Olivier Cochard-Labbé
FreeNAS main developer
http://www.freenas.org
Skype: callto://ocochard