Vinum performance

Chuck Swiger cswiger at
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 
> slow.

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.


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