Mihai - I was trying to avoid having to do this, hence my initial enquiry ;) OK Here goes... Tested software RAID1 with bonnie++ and was impressed by the figures... Then tried to use the same array set with the same kernel(2.14.17) with CONFIG_BLK_DEV_ATARAID_PDC et.al...... Completely screwed things up I could not be asked to recover the RAID ;) So I ended up doing a fresh install of rh7.2 on a single disk /dev/hde(no software RAID)... Recompiled the kernel 2.14.17 with CONFIG_BLK_DEV_ATARAID_PDC etc And booted this kernel off a floppy and managed to get the OS up... HOWEVER looking at dmesg PDCRAID version was 0.03beta it managed to recognize my RAID setup(done after the install via the promise controller)but did do nothing with it ! The disks obviously needed syncing but no errors were generated ! I must have missed something maybe the md subsystem ? As it stands the kernel manages to mount /dev/ataraiod/d0p1 and recognized RAID1 configuration but the disk read/writes are to one disk only named /dev/hde. I may have some more ideas to try to get this working but if anyone can throw over some suggestions all the merrier.... Noted : the ataraid howto specified that the driver is only RAID1 compatible ? Many thanks in advance. Shaf Shaf - shaf@xxxxxxxx - -----Original Message----- >From: "Mihai RUSU"<dizzy@xxxxxxxxx> >Sent: 28/12/01 17:28:56 >To: "Shaf Ali"<shaf@xxxxxxxx> >Cc: "linux-admin@xxxxxxxxxxxxxxx"<linux-admin@xxxxxxxxxxxxxxx> >Subject: Re: IDE Hardware RAID1 PDC20265 > >Hi > >On Thu, 27 Dec 2001, Shaf Ali wrote: > >> Out of curiousity whilst configuring 2.4.16 last night I noticed support for >> PDC20265 in RAID mode, has anyone tried this out - will this be better than >> software raid ? >> > >usually hardware RAID its better but it depends VERY much on the chip >included with the hard controller, also the performance difference depends >on RAID modes used. usually you want RAID-5 (and other checksumming RAID) >to run on hardware cards. > > >> Currently using Software RAID1(Redhat 7.2 + 2.4.16) - works like a charm : >> hot swapped the disk and added a new disk - hotraidadd and the new disk >> rebuilt just fine. >> > >somebody from the xfs-linux list said that he tested software raid and >hardware raid with good hardware cards and he didnt got any performance >boost for stripping raid modes (RAID-0) and mirroring (RAID-1) > >he said he got some performance with RAID-5 BUT that depends on the >controller (i dont think PDC are that good with RAID-5) > >i think its best to try it yourself and give us feedback on this list >(using bonnie++ like programs) > >---------------------------- >Mihai RUSU >"... and what if this is as good as it gets ?" > >
