Actually, the hard disks we use cost more than a whole PC (15,000 rpm SCSI) and ditto for the controller: http://www.neuse.net/products/server
To get HW RAID5 plus hot spare, HW adds up quit a bit for 4 of those bad boys. Regards, Jim Jim Ray, President Neuse River Networks tel: 919-838-1672 cell: 919-606-1772 http://www.Neuse.Net Neuse River Networks > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > Josh Vickery > Sent: Friday, December 08, 2006 9:39 AM > To: Triangle Linux Users Group discussion list > Subject: Re: [TriLUG] Setting Up RAID-5 > > CPU power may be cheap, but unless I'm mistaken, hard drives are even > cheaper. Have you considered multiple raid 1 arrays instead of a > single raid 5? The CPU overhead should be lower at the expense of > less disk space. It would also probably present the easiest recovery > situation, since any single disk in the collection would be usable all > by itself. > > Josh > > On 12/8/06, Matt Bidwell <[EMAIL PROTECTED]> wrote: > > Jason Tower wrote: > > > i'm sure someone can find my old post(s), but there are three major > > > problems with software raid: > > > > > > 1. the bootloader is installed on the MBR of the first disk only. if > > > that disk goes bye bye you're in trouble. sure, you can install > > > lilo/grub on multiple MBRs but that's a pita and an inelegant solution. > > > > > > 2. some sata chipsets flat out don't work with software raid 5, they > > > will crash the system hard either during initialization or under heavy > > > i/o. i've personally seen this happen on no less than three totally > > > different systems with multiple distros. > > > > > > 3. if a disk dies suddenly, the system is gonna crash regardless of raid > > > because the kernel can no longer communicate with /dev/sdx, it just > > > disappears. go ahead, set up software raid with hot swap disks then > > > yank one out while the system is running, see what happens. the data > > > itself is probably ok (you'll have a degraded array upon reboot) but > > > availability is shot. plus your fstab may no longer be accurate once a > > > disk is removed. > > > > > > there are probably workaround for these issues, or if they don't bother > > > you then knock yourself out with software raid. i use it myself if > > > circumstances justify it. but i've built enough systems to know that > > > hardware raid exists for a reason. if you want to do the job right get > > > a 3ware card and sleep peacefully. > > > > > > jason > > Jason, > > As per number one, here is how you write to /dev/md0, /dev/hda and > > /dev/hdc in lilo. It's straight from the software raid docs. > > > > boot=/dev/md0 > > root=/dev/md0 > > #this writes the boot signatures to either disk. > > raid-extra-boot=/dev/hda,/dev/hdc > > image=/vmlinuz > > label=RAID > > read-only > > > > As far as whether to do raid5 in software, I haven't done it. > > I do trust mdadm to do raid1. > > > > Matt > > -- > > TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug > > TriLUG Organizational FAQ : http://trilug.org/faq/ > > TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ > > > -- > TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug > TriLUG Organizational FAQ : http://trilug.org/faq/ > TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/
