On Tue, Nov 29, 2011 at 2:23 PM, Florian Philipp <[email protected]> wrote: > Am 29.11.2011 19:39, schrieb Michael Mol: >> On Tue, Nov 29, 2011 at 1:20 PM, Florian Philipp <[email protected]> >> wrote: >>> Am 29.11.2011 14:44, schrieb Michael Mol: >>>> On Tue, Nov 29, 2011 at 2:07 AM, Florian Philipp <[email protected]> >>>> wrote: >>>>> Am 29.11.2011 05:10, schrieb Michael Mol: >>>>>> I've got four 750GB drives in addition to the installed system drive. >>>>>> >>>>>> I'd like to aggregate them and split them into a few volumes. My first >>>>>> inclination would be to raid them and drop lvm on top. I know lvm well >>>>>> enough, but I don't remember md that well. >>>>>> >>>>>> Since I don't recall md well, and this isn't urgent, I figure I can look >>>>>> at the options. >>>>>> > [...] >>>>> What kind of RAID level do you want to use, 10 or 5? You >>>>> can also split it: Use a smaller RAID 10 for performance-critical >>>>> partitions like /usr and the more space-efficient RAID 5 for bulk like >>>>> videos. You can handle this with one LVM volume group consisting of two >>>>> physical volumes. Then you can decide on a per-logical-volume basis >>>>> where it should allocate space and also migrate LVs between the two PVs. >>>> >>>> Since I've got four disks for the pool, I was thinking raid10 with lvm >>>> on top, and a single lvm pv above that. >>>> >>> >>> Yeah, that would also be my recommendation. But if storage efficiency is >>> more relevant, RAID-5 with 4 disks brings you 750GB more usable storage. >>> >>> >> >> It looks like I'll want to try two different configurations. RAID5 and >> RAID10. Not for different storage requirements, but I want to see >> exactly what the performance drop is. >> >> I wish lvm striping supported data redundancy. But, then, I wish btrfs >> was ready... >> > > Just out of curiosity: What happens if you do `lvcreate --mirrors 1 > --stripes 2 ...`? Does it create something similar to a RAID-10 or does > it simply fail?
Hm. I don't know. Honestly, I didn't know about that functionality. Perhaps it's time I catch up on the docs again. -- :wq
