Message: 67 Date: Fri, 11 May 2007 11:40:25 +0800 From: Feizhou feizhou@graffiti.net Subject: Re: [CentOS] Re: Anaconda doesn't support raid10 To: CentOS mailing list centos@centos.org Message-ID: 4643E5A9.3030302@graffiti.net
Feizhou wrote: <snip>
The SCSI drive: Spindle Speed 15000 rpm Average latency 2.0 msec Random read seek time 3.50 msec Random write seek time 4.0 msec
The SATA drive: Spindle Speed 7200 rpm Native Command Queuing Y Average latency 4.16 msec Random read seek time <8.5 msec Random write seek time <10.0 msec Maximum interface transfer rate 300 Mbytes/sec
Compare to a 10K scsi drive: Spindle Speed 10,000 rpm Sustained data transfer rate 80 Mbytes/sec. Average latency 3.0 msec Random read seek time 4.9 msec Random write seek time 5.4 msec Maximum interface transfer rate 320 Mbytes/sec
The above specifications are about Performance. If maximum Reliability is the goal, look at the MTBF in the specifications. If the Design Engineers have done their job, and the Manufacturing Engineers maintain high Quality Control, the result should be a quality component.
As has been pointed out in this thread, RAID is *not* a substitute for backups. RAID is intended to keep the box up and running. Valuable data should always be stored off site, in removable drives, or via the WAN. Lanny