On Sat, Apr 26, 2014 at 8:32 PM, Gora Mohanty <[email protected]> wrote: > > Arun - I meant multiple partitions on each disk. E.g., three 1TB partitions > on a 3TB > disk, the idea being to minimise space lost. Also, on hardware RAID vs. > software
OK, I missed that. So are you planning to have 3 x 3TB disks (RAID5) with multiple partitions in each that will be members of different RAID devices i.e. /dev/md0, /dev/md1, ... , /dev/mdN? If that is the case, you will not gain any efficiency as others have also mentioned. Use the entire disk to create a /dev/md0 and the create a LVM on top of this device. You can carve up the LVM PV into LV partitions and create filesystems on them. The performance overhead of LVM on top of mdadm is small but gives you a lot of flexibility for growing the file systems in case you need more space. > RAID, my impressions from reading blogs was that: (a) Performance penalty is > small. Yes, I get your point about the parity calculations being more > complex for > RAID 5/6, but how big s that? According to my storage vendor colleague mentioned earlier, sufficient to go for hardware raid where all the parity calculations are done by the RAID card. > (b) There are horror stories about how > hardware RAID > partitions become non-recoverable if the particular RAID controller card > dies. Even > a replacement of the same model sometimes does not work. These might be war > stories, but they scare me. Yes, there is some truth to it but now vendors give assurance that same model should recover the RAID volumes defined by another RAID card. Areca mentions this specifically but I have not had the luxury of a spare card to test it out! As always, keep backups of critical files in a secondary storage. I have had 'ooops' with mdadm RAID also, where it goes into degraded mode w/o any reason and I have had to manually restore the members into the device. > I guess that I can try and experiment with read/write speeds with RAID6. Please share your results. -- Arun Khan Sent from my non-iphone/non-android device (অরুণ খান্/अरुण खान) I'd rather be called a moron, than walk around with doubts in my mind. _______________________________________________ Ilugd mailing list [email protected] https://lists.hserus.net/mailman/listinfo/ilugd
