Greg Wooledge <g...@wooledge.org> writes: > to...@tuxteam.de (to...@tuxteam.de) wrote: >> > 1x 4TB, single drive, 3.7 TB, w=108MB/s , rw=50MB/s , r=204MB/s >> > 2x 4TB, mirror (raid1), 3.7 TB, w=106MB/s , rw=50MB/s , r=488MB/s > >> Thanks. Real data :) >> >> The doubling in read throughput is somewhat surprising to me. Some >> learning to do, it seems. > > There are two copies of everything. So, if you need to read a big > file, you can read half of it from disk 1 and the other half from disk 2, > roughly simultaneously.
I have a vague memory of reading once that mdraid doesn't stripe reads to a single file. I.e. with raid1 you get the double speed if you read different files (or different parts of disk) but reading a single file, no. So is this different in zfs? I guess I could test this myself. The way Bonnie++ was used for those results above is definitely parallel.
