cswiger at mac.com
Fri May 30 08:22:17 PDT 2003
Per olof Ljungmark wrote:
[ ... ]
> The bottleneck is write performance, reading from the documentation this
> is normally a weak point in Vinum/raid5 setups.
It's not vinum; RAID-5 write performance is going to be relatively slow even
with hardware parity/XOR support.
> The volume will be used for storing temporary files with sizes in the
> 1-4MB range, a few hundreds at a time. Reads are fine but writes a bit
What ratio of reads to writes do you expect?
> Copying 170 files total 319MB TO the Vinum volume takes about 2m45s.
> Copying same files FROM the Vinum volume to another volume on a hardware
> raid5 controller takes 43s.
A 3-1 ratio in speeds for software RAID-5 versus hardware doesn't strike me as
being very wrong....
> This machine is not in production yet so I can still make changes to the
> configuration. The current block size is 16384 and the stripe size 419k.
> I assume it would be a good idea to change that to for example 491,520?
...or try a few stripe sizes, such as 64K or 128K.
More information about the freebsd-questions