Hosting again

[Dirk Koopman]

Martin A. Brooks wrote:
> 
> Given Adaptec have managed to release some of the most  shamelessly crap 
> bits of RAID kit I've ever had the misfortune to use,

Yes, but they were not alone.

> 
> 3ware/Compaq/Mylex hardware raid >
> software RAID >
> Crappy hardware RAID that's really software RAID and/or Adaptec
>

Depends what you want. Unless the processors in RAID cards have been 
significantly beefed up in recent hardware - if it is speed you want - 
then software raid wins hands down all the time.

The last time I did some serious benchmarking (3 or 4 years ago now) 
software raid beat so called "enterprise" raid hardware - in speed - 
(both read and write) by a factor of between 4 and 5 (depending on raid 
card manufacturer). IIRC I tested again high end Adaptec and Compaq raid 
cards as installed in Dell and Compaq servers respectively. Ironically 
this benchmarking was done using the same card either as a raid 
controller or just plain scsi. Software raid was always much faster.

Sadly though, software raid was harder to setup, to maintain and to 
rebuild after a failure. So it wasn't all good news. Don't know whether 
the tools have improved since then (I hope so). Don't do that anymore.

None of this should be hugely surprising as, in those days, the 
processor on board the raid card was some otherwise obsolete 400Mhz 
Intel part with maybe as much as 256Mb of ram as cache. At the same 
time, the servers they were in were dual 2GHz+ Xeons or some such with 
4GB RAM. And as these thing were just used basically as file servers, it 
is easy to see the reason for the discrepancy.

Don't take your hardware manufacturer's word for it. Use bonny, it will 
tell how well it *really* works.

Dirk