[SATLUG] RAID5 & ddrescue
hc at lookcee.com
Sun Aug 23 10:53:32 CDT 2009
David Labens wrote:
> First, since none of the data drives were mounted, I shut down the server and removed all the data drives except /dev/sdc. Then, I installed the new drive on the cable that had /dev/sda.
> Then, I ran fdisk and created a new primary partition. Strangely enough, it would only allow me to create /dev/sda, not /dev/sdf that I WANTED to create, just to prevent confusion. But, confusion had already set in.
> Then, I went to use ddrescue:
> ddrescue --no-split /dev/sdc /dev/sda logfile
> Strangely enough, it quit after 80 gb was copied. So, I examined the drives and found that /sdc was no longer the bad drive, but was now my 80 gb OS drive, and my bad drive was now /sdb (by examining & comparing serial numbers). Fortunately, it had not turned the bad drive into /sda, so my bad data was still intact.
> I tried rerunning the command, this time with the proper source drive, but it consistently started running it at the 80 gb point where the first command had stopped.
> So, I had to fdisk to remove the partition, write it to the system & exit, then run fdisk to create the partition & write it to the system & exit.
> Here is the current output ...
> root at RCH-SERVER:/# ddrescue --no-split /dev/sdb /dev/sda resclog1
> Press Ctrl-C to interrupt
> Initial status (read from logfile)
> rescued: 0 B, errsize: 0 B, errors: 0
> Current status
> rescued: 17471 MB, errsize: 233 kB, current rate: 54525 kB/s
> ipos: 17471 MB, errors: 4, average rate: 52466 kB/s
> opos: 17471 MB
> Copying data...
> You can see that there are already 4 errors, but it's still working.
> Updates will be forthcoming as progress is made.
> But, I DO have a question... When I go back to reassemble the array (after re-connecting everything), will the system automatically know which /sda is the copy of the /sdc that became the /sdb???
Sorry David kant resist, Whos on first? Yes!
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