I'm experimenting with mdadm and nbd. I have no idea if this is a good or really bad idea but my observations are: less mdadm.conf DEVICE /dev/nbd1 /dev/nbd2 /dev/nbd3 ARRAY /dev/md0 level=raid5 num-devices=3 devices=/dev/nbd1,/dev/nbd2,/dev/nbd3
hdparm timings:
/dev/nbd1: Timing cached reads: 1248 MB in 2.00 seconds = 623.38 MB/sec Timing buffered disk reads: 30 MB in 3.12 seconds = 9.63 MB/sec
/dev/nbd2: Timing cached reads: 1196 MB in 2.00 seconds = 597.05 MB/sec Timing buffered disk reads: 22 MB in 3.00 seconds = 7.33 MB/sec
/dev/nbd3: Timing cached reads: 1200 MB in 2.01 seconds = 598.47 MB/sec Timing buffered disk reads: 30 MB in 3.19 seconds = 9.39 MB/sec
/dev/md0: Timing cached reads: 1204 MB in 2.00 seconds = 600.53 MB/sec Timing buffered disk reads: 2 MB in 4.00 seconds = 511.88 kB/sec
Is this caused by: mythtv@server etc$ cat /proc/mdstat Personalities : raid5 raid4 md0 : active raid5 nbd33 nbd21 nbd10 594870656 blocks level 5, 64k chunk, algorithm 2 3/2 UU_ >.................... recovery = 1.4% (4243452/297435328) finish=2421.2min speed=2016K/sec
unused devices: <none>
also being rather slow at 2016K/sec
Please any comments/advice how to improve
Henk Schoneveld The Netherlands