Re: Million files or so on RAID 5 Partition

["Martin K. Petersen" <mkp@linuxcare.com>]

>>>>> "Simon" == Simon Matter <simon.matter@ch.sauter-bc.com> writes:

Simon> Martin Spott schrieb:
>>
>> > I have a 8 disk RAID 5 partition (8 X 9 GB) on a split bus Compaq
>> > array [...]
>>
>> Just to be curious (as always ....): Do you use the old 'md' driver
>> for this or LVM ? Should I stay away from one of these (despite the
>> issues with internal log on RAID5) ?

Simon> IIRC you can not use LVM to create RAID5 devices, just
Simon> RAID0,1. 

Correct.  MD and LVM are orthogonal.

Think of MD as a way to improve redundancy and/or performance.  And
LVM as a dynamic partitioning scheme.

Forget about the striping features of LVM.  MD RAID0 is a lot faster.


Simon> Anyway it seems to be not so sure that we always have a working
Simon> LVM for every kernel (Isn't it broken at this time for
Simon> 2.5?). MD should be more safe here.

And yet neither LVM nor MD are big I/O safe in 2.5 yet.

-- 
Martin K. Petersen, Principal Linux Consultant, Linuxcare, Inc.
mkp@linuxcare.com, http://www.linuxcare.com/
SGI XFS for Linux Developer, http://oss.sgi.com/projects/xfs/