Hi >On Sun, 13 Apr 2014, John Cox wrote: >> Hi >> >> I'm running OpenBSD 5.4 (dmesg below) with softraid in mirror mode. >> One of the drives failed so I replaced it - the first time that RAID >> has actually saved my data as opposed to simply making my life harder! >> Thank you softraid. >> >> They are 3T drives and it looks like the rebuild is going to take ~5 >> days to do. Is this expected? Is there any config parameter that I >> should have set up to improve performance? 5 days = ~7MBytes / sec >> and I know the drives can run a lot faster than that. > >The current code is designed to be robust rather than fast - it does a read >from one of the online chunks (in this case you presumably only have one of >those) and then does a write to all chunks (including both the online ones >and the rebuilding one). In order to speed things up you want to read from >one online chunk and only write to the chunk that needs rebuilding - the >problem with this is that you need to prevent changes to the blocks that you >are rebuilding until that write completes. Unfortunately that means some more >restructing and additional code, plus a whole bunch of testing...
Why do you need to prevent update? Surely if a new write arrives for that block then you simply schedule it on top of the previous write, your data integrity will be no worse than you had with the previous "degraded" state of that block. >> Can I reboot the system during the rebuild or if I do will it start at >> the beginning again? I could try it but I'm now about 3 days in and >> don't wish to waste it. > >The rebuild progress is stored in the softraid metadata - if you reboot (or >even if the power goes out) it should pick up where it left off and complete >the rebuild. Good Oh! I was expecting that that was the case but felt disinclined to test it. Thanks JC
