A little note... We tried to build a software-driven RAID-5 configuration on a single RAID IDE Controller (you can scrap the RAID feature since we are only after the IDE Controller) and it is sooooooo slowwwww. The test machine was a P4-1.5 with 256 RDRAM. Well that did not matter when all the linux PC was doing was to broadcast the checksum packets on all of the four disks... =)
But when we tried moving 2 of the drives to the built-in IO Bus of the motherboard, we were able to cut the write time in half... I almost forgot, the read was fast enough but the write was unbearable. The problem that arose with this configuration was there were unsynchronized data writing everywhere and the RAID checksum failed about every 6 hours which requires a resync of checksum data which on a 4x40GB Seagate Barracuda would take a day... So you basically get the picture... =) Kranasian Soul X Dan Cedric Delima NEC Telecom Software Philippines, Inc. ------------- Articulus Primus Daelestini Soldevi Solembe Malatires Hexine ----- Original Message ----- From: "Ian C. Sison" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, May 19, 2002 5:00 PM Subject: Re: [plug] IDE vs SCSI RAID > On Sun, 19 May 2002, Rick Moen wrote: > > > Quoting Ian C. Sison ([EMAIL PROTECTED]): > > > > > ...faster access (UDMA 133).... > > > > A mirage and an irrelevancy. That's the theoretical maximum transfer > > rate of the bus, which can never be approached even in ideal cases, > > because data flow is limited to the physical read speed of hard drives, > > An issue which is just as relevant on SCSI based solutions > > > and ATA cannot draw data from more than one drive at a time on an ATA > > channel. I hear of some contrived test situations where it's starting > > to be possible to saturate ATA/66, but just barely. > > Most Hardware IDE RAID controllers recommend one disk per ATA channel > anyway, so it's a non-issue. > > > > _ > Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph > To leave: send "unsubscribe" in the body to [EMAIL PROTECTED] > > To subscribe to the Linux Newbies' List: send "subscribe" in the body to [EMAIL PROTECTED] > _ Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph To leave: send "unsubscribe" in the body to [EMAIL PROTECTED] To subscribe to the Linux Newbies' List: send "subscribe" in the body to [EMAIL PROTECTED]
