I'm just setting up a SuperMicro system which has twin SATA disks on an Intel IHC7 RAID-capable controller. The system came with Fedora 5 pre-installed, which I will be removing and replacing with CentOS 4.5. But before doing so, I've been having a look at how the original vendor configured it. When I've built systems previously, I've disabled any RAID controller and used kernel software RAID-1, set up per-partition, and this has worked well. This system is currently set up with hardware RAID enabled, which is detected by the kernel device mapper. I can see what it has found using "dmraid" with -b, -r and -s. A single physical volume was created on the mapped RAID-1 device, and then logical volumes created on that. My question is: which kind of configuration will generally give me better performance? To use the IHC7 RAID-1 as currently set up, or to use Linux software RAID-1 as I am used to doing? Any other reasons to choose one over the other? Thanks in advance for any insights. Cheers Tony -- Tony Mountifield Work: tony at softins.co.uk - http://www.softins.co.uk Play: tony at mountifield.org - http://tony.mountifield.org
Tony Mountifield spake the following on 7/17/2007 10:32 AM:> I'm just setting up a SuperMicro system which has twin SATA disks on an > Intel IHC7 RAID-capable controller. > > The system came with Fedora 5 pre-installed, which I will be removing and > replacing with CentOS 4.5. But before doing so, I've been having a look at > how the original vendor configured it. > > When I've built systems previously, I've disabled any RAID controller and > used kernel software RAID-1, set up per-partition, and this has worked > well. > > This system is currently set up with hardware RAID enabled, which is > detected by the kernel device mapper. I can see what it has found using > "dmraid" with -b, -r and -s. A single physical volume was created > on the mapped RAID-1 device, and then logical volumes created on that. > > My question is: which kind of configuration will generally give me better > performance? To use the IHC7 RAID-1 as currently set up, or to use Linux > software RAID-1 as I am used to doing? Any other reasons to choose one > over the other? > > Thanks in advance for any insights. > > Cheers > TonyI won't go into the whole "fakeraid" rant, but the software raid drivers are very mature and have been working well for years, but the dmraid code is much newer, and probably not quite as stable. -- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!
use only the linux software raid. It's perfectly stable even under high loads here. Tony Mountifield wrote:> I'm just setting up a SuperMicro system which has twin SATA disks on an > Intel IHC7 RAID-capable controller. > > The system came with Fedora 5 pre-installed, which I will be removing and > replacing with CentOS 4.5. But before doing so, I've been having a look at > how the original vendor configured it. > > When I've built systems previously, I've disabled any RAID controller and > used kernel software RAID-1, set up per-partition, and this has worked > well. > > This system is currently set up with hardware RAID enabled, which is > detected by the kernel device mapper. I can see what it has found using > "dmraid" with -b, -r and -s. A single physical volume was created > on the mapped RAID-1 device, and then logical volumes created on that. > > My question is: which kind of configuration will generally give me better > performance? To use the IHC7 RAID-1 as currently set up, or to use Linux > software RAID-1 as I am used to doing? Any other reasons to choose one > over the other? > > Thanks in advance for any insights. > > Cheers > Tony-- My "Foundation" verse: Isa 54:17 No weapon that is formed against thee shall prosper; and every tongue that shall rise against thee in judgment thou shalt condemn. This is the heritage of the servants of the LORD, and their righteousness is of me, saith the LORD. -- carpe ductum -- "Grab the tape" CDTT (Certified Duct Tape Technician) Linux user #322099 Machines: 206822 256638 276825 http://counter.li.org/
Tony Mountifield
2007-Jul-18 12:19 UTC
[CentOS] Re: IHC7 RAID-1 or Kernel Software RAID-1?
In article <f7iufv$1cc$1 at softins.clara.co.uk>, Tony Mountifield <tony at softins.clara.co.uk> wrote:> > My question is: which kind of configuration will generally give me better > performance? To use the IHC7 RAID-1 as currently set up, or to use Linux > software RAID-1 as I am used to doing? Any other reasons to choose one > over the other?Thanks for the responses, confirming what I thought: disable SATA RAID and use Linux software RAID for mirroring. So that's what I've done. It appears that my Centos 4.4 install didn't know about dmraid devices anyway. Cheers Tony -- Tony Mountifield Work: tony at softins.co.uk - http://www.softins.co.uk Play: tony at mountifield.org - http://tony.mountifield.org