> [email protected] wrote: >> My Asus MB uses an onboard Nvidia "software RAID" that is controlled >> at the bios level. The only involvement for the 'nix OS is to ensure >> that the kernel can see the array properly (which was no picnic). > > Any reason why you stuck with the proprietary software RAID? In addition > to the difficulty you apparently had getting it to work initially, if > you need to change controllers or motherboards, and expect to keep the > array running, you'll probably be out of luck. > > >> I am not sure how one even determines if it's an issue. > > I guess you'd have to go back to the fundamentals and look for the load > average increasing or iowaits. But if you determine that the RAID is a > problem, I don't know what options you'll have for correcting it. > Perhaps there are BIOS settings that permit you to tune it. > > So given that you aren't using mdadm, how do you know that the Nvidia > software RAID is even performing a periodic rebuild? Or are you just > suspicious that the RAID layer in general may be introducing performance > bottlenecks? >
Hi Tom, Thank you for this feedback. My limited expertise is dangerous in that I can follow directions well, but often don't know enough of what is really going on. When I purchased my system that is being used for my backend, it was my understanding that the onboard RAID controller was hardware based. It is not. The MB is an Asus M2N-SLI Deluxe. This system is set up in a dual boot arrangement with Windows XP Pro 64. I was under the understanding that the only software available to setup, maintain, or change the array was Nvidia's Mediashield which only runs in Windows. (note that I rarely boot into Windows unless Im using this) When I opted to add more storage space to my Mythbox, I decided that RAID 5 seemed like a better option than my current RAID 1 mirror setup with two 350 GB drives. Note that the existing dual boot arrangement was using bootable RAID. I added two more identical drives and migrated from a two drive RAID 1 mirror to a four drive RAID 5. When I went to boot back to nix, it was broken. It turned out that the stock Mandriva Kernel at that time did not support RAID 5; only RAID 0 and 1. I was fortunate to get support from one of Mandrivas kernel hackers which supplied me with the kernel that would work and I had to manually add the dmraid4-5 module and redo my initrd with it in place. After that nix saw the array and all was apparently well. The new challenge at this point was that I had a RAID 5 setup with a partition size no different than my original RAID 1 which was ~ 300+ GB. I had to grow my home partition to use the new space made available in the array. I was able to do this in the nix OS GUI. After this may have been when my problems started, but it may have also have been when I made the change from RAID 1 to RAID 5. I cant be sure because it took a long time to get the commands right to get the array to grow and I ran with the RAID 5 original partition some for some time. After you mentioned the maintenance of the array I started to wonder. Does nix handle this for me in the dmraid4-5 module? Should I be setting something up in mdadm? I know nothing about this at this point. Is there a way that I can see if I am really just using a Linux software RAID setup like yours? Since receiving your email I decided to boot into Windows and run an array synchronization in the Nvidia Mediashield software. I successfully played about 20 minutes of a recording this morning afterwards with no stuttering, but havent really had an opportunity to do much testing yet. Can you offer some additional thoughts? I am curious how often one needs to maintain the RAID 5 array to make sure problems dont arise. Saying this, I cant be sure if Ive fixed anything yet. If things are still giving me grief, one option I have is to migrate my array back to RAID 0 and give up on failure protection. I hate to do that, and Id want to be sure that my drives are really the problem before doing that. I still struggle with the fact that it only appears to be the MVPs that have issues in this regard. Why dont the other PC based frontends have similar issues? Do they buffer the data differently? Scott ------------------------------------------------------------------------------ _______________________________________________ Mvpmc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mvpmc-users mvpmc wiki: http://mvpmc.wikispaces.com/
