I am looking to replace upgrade a current drive from 3 TB to 5 TB. Due to a system freeze (which is another story) the machine had to get rebooted, so it started a partity "check nocorrect". The check returned this:

Feb 27 12:57:15 VVData kernel: md: recovery thread: PQ incorrect, sector=18302032
Feb 27 12:57:15 VVData kernel: md: recovery thread: PQ incorrect, sector=18302096
Feb 27 12:57:15 VVData kernel: md: recovery thread: PQ incorrect, sector=18302104
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670056
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670064
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670072
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670080
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670088
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670096
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670104
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670112
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670120
Feb 27 12:57:22 VVData kernel: md: recovery thread: P incorrect, sector=18670128

It finished last night with this:

Feb 28 18:53:45 VVData kernel: md: sync done. time=107974sec
Feb 28 18:53:45 VVData kernel: md: recovery thread: completion status: 0

I then came in this morning expecting to replace the drive and found the partiy check at 30.5%! After flipping out and then realising that it was doing its monthly check, I looked at the logs an found this:

Mar  1 00:00:01 VVData kernel: mdcmd (58): check 
Mar  1 00:00:01 VVData kernel: md: recovery thread: check P Q ...
Mar  1 00:00:01 VVData kernel: md: using 2304k window, over a total of 4883770532 blocks.
Mar  1 00:00:04 VVData kernel: md: recovery thread: P corrected, sector=60672
Mar  1 00:00:04 VVData kernel: md: recovery thread: P corrected, sector=60680
Mar  1 00:00:04 VVData kernel: md: recovery thread: PQ corrected, sector=60952
Mar  1 00:03:24 VVData kernel: md: recovery thread: PQ corrected, sector=18302032
Mar  1 00:03:24 VVData kernel: md: recovery thread: PQ corrected, sector=18302096
Mar  1 00:03:24 VVData kernel: md: recovery thread: PQ corrected, sector=18302104
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670056
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670064
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670072
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670080
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670088
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670096
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670104
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670112
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670120
Mar  1 00:03:28 VVData kernel: md: recovery thread: P corrected, sector=18670128
Mar  1 00:03:28 VVData kernel: md: recovery thread: PQ corrected, sector=18679960
Mar  1 00:03:28 VVData kernel: md: recovery thread: PQ corrected, sector=18679968
Mar  1 00:03:28 VVData kernel: md: recovery thread: PQ corrected, sector=18679976
Mar  1 00:03:28 VVData kernel: md: recovery thread: PQ corrected, sector=18679984
Mar  1 00:03:28 VVData kernel: md: recovery thread: PQ corrected, sector=18679992
.
.
.
Mar  1 04:39:38 VVData kernel: md: recovery thread: stopped logging

My questions are:

1. Should I rerun the parity check with correct enabled before I replace the drive?
2. Can I write data to the server while the parity is running?
3. If I do write data to the server while the parity check is running, won't the parity check be off (since new data is now on the data drives)
4. Should I wait to replace a drive until there are zero errors after a parity check.

 

Thank you for any help!

 

Edited March 1, 20179 yr by micokeman

1. Yes
2. Yes
3. No, The new data will update parity when it is written.
4. Yes.

Of course, any reads or writes during the parity check will affect performance. How much writing did you have in mind?

Thank you!

 

There wouldn't be much writing. Actually, there would be some deleting of duplicate files (same content, but named differently), but not adding.