On Sat, 8 Mar 2008, Rudi Ahlers wrote: > > > > On Sat, March 8, 2008 19:18, Mogens Kjaer wrote: > Scott R. Ehrlich wrote: >> I have a Dell PowerEdge 2950 with 6 SAS disks and a PERC 5/i controller >> what won't do RAID 6. I plan to have 2 drives as RAID 1 for the OS, and >> the remaining 4 as RAID 6. Granted the PERC can do RAID 1, I'm tempted >> to do everything via software RAID. Thus, if anything goes wrong with >> the controller, I just need to obtain a new SAS controller and I'm back >> up. > > 4 disks in RAID 6? Isn't this a bit overkill? You would use half > the space for RAID checksums. > > If it were me, I would: > > Partition all drives identically with a 200M partition 1 > and the rest as partition 2 > > Use sda1 and sdb1 in RAID 1 as /boot > Use sd[cdef]1 as swap in RAID 5 > Use sd[abcdef]2 as / in RAID 5 > > You could use RAID 6 for /, but then you're not 100% > safe if you loose disks 1 and 2 simultaneously. > > Mogens > > -- > Mogens, RAID 5 can only handle 1 drive failure. So, if he had 3 drives in > he set & 1 spare, then that 1 spare will be used to rebuild te stripe, > which could take long if it's big. If something goes wrong during this > period, he could effectivly loose all his data. So he'll be as screwed > (sorry, I couln't think of a better word) as if he had to loose 2 drives > in RAID 6 stripe > > RAID 6 with 4 drives will give the same volume, since all 4 drives are > used, but offers 2 drive failure. > > I would suggest rather use RAID 10 (this is 2x RAID 1 stripes, stripped > together as RAID 0), as it will give you better performance and will be > much more reliable What would be the recommended way to create a software RAID 10 array? Again, two disks for the OS as s/w RAID 1, the remaining four disks for data as RAID 10, with possibly 1 of the 4 as a [hot] spare. Thanks. Scott > > > -- > > Kind Regards > Rudi Ahlers > CEO, SoftDux > Website: http://www.SoftDux.com > Forums: http://Forum.SoftDux.com > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >