[CentOS] Re: Anaconda doesn't support raid10

Thu May 10 08:05:06 UTC 2007
Andreas Micklei <andreas.micklei at ivistar.de>

Am Donnerstag, 10. Mai 2007 schrieb Feizhou:
> > Probably not, but is SATA really much worse then SCSI or SAS?  I did
> > some testing on a dell PE 2950 of 750GB SATA's vs SAS and SCSI drives,
> > and the SATA drives seem to be faster at least at first glance.  I don't
> > have good numbers from the  SCSI tests, but at least for sequantial, I'm
> > getting a better speed off the SATAs.
> sequential will be better than SCSI due to the packing on those platters
> which make up for the lack in rpm. NCQ should even up the random ability
> of SATA disks versus SCSI drives but that support has only become
> available lately on Linux and you also need the right hardware (besides
> the right disks).

SAS and SCSI really has it's place when you need random access with lots of 
IOs per second, i.e. Fileserver, Database Server. We upgraded our Fileserver 
(NFS, Samba) from SATA SW Raid to SCSI HW Raid and the difference is HUGE. 
One the old system a single user doing a large file copy could bring the 
system almost to a halt. On the new system you do not even notice if one user 
does a similar operation. However plugging one of the same SCSI discs into 
your average PC will not give you much advantage.

There is also a line of SATA discs that aim for the low-end server market, the 
WD-Raptors. They spin at 10.000 rpm and give much better random access 
performance than normal SATA drives. The price point is very attractive 
compared to SCSI and SAS. Great alternative for a tight budget.

Here is my favorite site for comparing drives. Has nice background articles 

Andreas Micklei

Andreas Micklei
IVISTAR Kommunikationssysteme AG
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