On Sun, 13 Jul 2003 19:15, Andrea Venturoli wrote: > ** Reply to note from "Greg 'groggy' Lehey" <[EMAIL PROTECTED]> Sat, 12 Jul > 2003 17:13:29 +0930 > > > The real performance penalty for RAID-5 is simply that writes require > > so much I/O. Expect 25% of the write performance of RAID-0. > > Ok, I must ask this: > Shouldn't SCSI system allow paralell writes on different disks?
Physical writes yes. But how does the data get there? The SCSI bus (like any other) has a finite bandwidth. But maybe if you are very clever you can coax the SCSI bus into transmitting the same information to all disks in parallel. > If so, why so much penalty? Malcolm Kay _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
