Heya again :) Hmmm, okie, what happens if one drive fails and you don't have a spare at that time? Can u just halt, remove the faulty drive, boot back and keep using only 2 drives till the 3rd one comes in? Then install the 3rd one and watch raid5 "terminator 2" itself back together? Or does it require to have all 3 drives installed at all times?
I guess rearanging drives in RAID 5 is bad.... really bad, right? Like you can't have a,b,c and then by mistake put b,a,c md driver doesn't have bad block relocation, is it useful at all if you can just replace the drive that causes the problem? Thanky again in advace for your response :) On Thursday 24 October 2002 03:06, Jeff Waugh wrote: > <quote who="Yuri"/> > > > a) How do you know when one of the harddrive fails? Do i have to look in > > the messages all the time for it or will it ( or can i make it) beep on > > bootup or smth like that to let me know that it failed? > > cat /proc/mdstat ... From mine (software RAID-1): > > Personalities : [raid1] > read_ahead 1024 sectors > md0 : active raid1 ide/host0/bus1/target0/lun0/part2[0] > ide/host0/bus0/target0/lun0/part2[1] 38832576 blocks [2/2] [UU] > > unused devices: <none> > > Those two U's mean "up". :-) It also gives you a cute little status bar > whilst the drives are syncing. Also, most distros will have a cronjob that > mails you if a hard drive has failed. > > > b) Is it CPU-intensive? I have 4 drives right now in P133 with 98MBram > > all using Promise cards and it's running 2.4.18-xfs kernel (rh7.2), and > > not sure if my setup will handle RAID-5. > > RAID is pretty simple stuff, so it's usually I/O speed that you should look > into if it's important to you. The gnome.org machines run on software > RAID-5, and we haven't had too many problems... However, if there are lot > of writes going on, it will take a fair bit of cpu / kernel time. > > > c) This is silly, but can i add more drives later to that RAID-5? Like > > another 1 or 2 drives and not loose anything, or should i be looking at > > LVM rather than raid5? > > Because of the way the data is laid out, you can't add more drives later > with RAID-5 without backing up and creating a new array. However, if you're > just interested in more redundancy, you can create a RAID-5 array of RAID-1 > arrays. This sounds silly, but sometimes it's useful. > > LVM is worth looking at, but is going to change in 2.6 anyway. :-) > > - Jeff -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
