Changing tunables during rebuild

[mvdzwaan]

I was just wondering if it is allowed to change the tunables during a disk rebuild (5.0rc6 test2) ?

 

Will it have any effect on the current performance, or is a reset required, and will it not interfere with the rebuilding (leading to corrupt rebuild).

 

I'm asking because I am in the process of upsizing my disks to 3Tb (4tb parity just to be sure). The parity rebuild was at 50Mb/sec, the first disk rebuild ~40Mb/sec, but the next disk (and I'm also looking at hw failure of the disk but my syslog and smart reports are 100% clean) the disk rebuild is between 10~30Mb/sec and it's fluctuating constantly.

 

Yesterday I was writing to one of the new disks and the write speed was also not constant (10MB/s ~45MB/s, fluctuating in nice wave pattern on the new Windows 8 file transfer dialog).

[mvdzwaan]

I've stopped the rebuild and put in another new disk, and this one is going at 50MB/s.

 

So I have a bit of work to do to see why the previous new disk did not have this performance, but smart reports were perfect, smart test was perfect, pre-clearing went without problems and fast etc.