Hi,
I'm still reshaping a 2 disk raid5 to 3 disks. It has now progressed
past the 50% mark so all data has been reshaped. So now the kernel
simply writes zeroes (I assume) to all 3 disks. There are no more
reads, only writes.
Now what is odd is the cpu usage:
/proc/mdsata:
md0 : active raid5 sdd1[3] sdc1[2] sda1[0]
3907015168 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
[============>........] reshape = 62.0% (2425537964/3907015168) finish=22
0.0min speed=112230K/sec
iostat -k 10:
Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
sda 834.40 0.00 103372.60 0 1033726
md0 0.00 0.00 0.00 0 0
sdc 813.90 0.00 104601.80 0 1046018
sdd 718.50 0.00 104499.40 0 1044994
top:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2058 root 20 0 0 0 0 R 96 0.0 1106:40 md0_raid5
18379 root 20 0 0 0 0 R 50 0.0 324:11.19 md0_reshape
Is the kernel zero filling the raid device and computing the XOR of
zeroes for the parity blocks? Wouldn't it be less cpu consuming to
insert zero filled stripes directly into the stripe cache?
MfG
Goswin
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