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Re: [linux-lvm] Disk crash on LVM



Hi

I'm a bit confused about how pvmove works now...
I have done alot och pvmove on the same PV now and the total percentage of all the pvmoves is alot bigger than 100%
17%+21%+7%+5%+67%+5%+.....

Why is that?

thanks
/Fredrik



----- Original Message ----- From: "Fredrik Skog" <fredrik skog rodang se>
To: "LVM general discussion and development" <linux-lvm redhat com>
Sent: Tuesday, September 22, 2009 3:43 PM
Subject: Re: [linux-lvm] Disk crash on LVM


Hello again,

Is there any way to see how much the total progress of pvmove is? I now have issued the command 7-8 times with different amount of progress. And I have no idea how much is remaining of the total.

Thanks
/Fredrik


----- Original Message ----- From: "Fredrik Skog" <fredrik skog rodang se>
To: "LVM general discussion and development" <linux-lvm redhat com>
Sent: Tuesday, September 22, 2009 3:27 PM
Subject: Re: [linux-lvm] Disk crash on LVM


Hi

I'll update you on the progress with my crashed hd.
I'm not yet finished with the pvmove from the device because it won't work for very long at a time. If I have the drive in room temperature and then put it in the freezer for 25-30mins it works for maybe 15-20min (the drive still in the freezer)and i get a pvmove progress of about 15-20%. If I then shut it down and just let it cool again I get maybe 5-7% more out of it before it dies.Prolonging the time in the freezer doesn't seem to help at all, in fact sometimes it's worse and the drive doesn't start at all. The drive seems to need a few hours warm-up time after it's been frozen and then stopped working before I can refreeze it again. It takes ridiculous amounts of time fiddling with this, but I hope to get to the finish soon.
I have not yet tried to increase the readahead.

/Fredrik


----- Original Message ----- From: "Peter Keller" <pkeller globalphasing com>
To: "LVM general discussion and development" <linux-lvm redhat com>
Sent: Monday, September 21, 2009 1:27 PM
Subject: Re: [linux-lvm] Disk crash on LVM


Coming a bit late to this thread...

On Sat, 19 Sep 2009, Fredrik Skog wrote:

Thanks guys for your input on the matter.
I lenghtened the power cables and bought a full lenght SATA cable. Now the disk is in the freezer and in progress with pvmove. 10% now. so far so good. The reason i decided for the pvmove instead of dd or dd_rescue was the fact
that i tried a pvmove before, so the process was already started but it
stopped working on 1%. Now with a frozen and working disk it continued from
where it left off.

I have found that with sequential reads like this, adjusting the readahead of the device with something like 'blockdev --setra nnn' can dramatically
shorten the time needed to read the whole device.

The default usually seems to be too low when reading sequentially. If you haven't already adjusted it, try adjusting it upwards. Values like 8192 or
16384 may help.

Good luck,
Peter.

I can tell you how it turned out later.

Thanks

/Fredrik



----- Original Message ----- From: "André Gillibert" <rcvxdg gmail com>
To: <linux-lvm redhat com>
Sent: Saturday, September 19, 2009 4:11 PM
Subject: Re: [linux-lvm] Disk crash on LVM


Ray Morris <support bettercgi com> wrote:
[...]
   Then dd from the old copy of the LV to the new:

dd if=/dev/org/$1 bs=64M iflag=direct |
dd of=/dev/copy/$1 bs=64M oflag=direct

   That piped dd is 2-3 times faster than the "obvious"
way to run dd.
[...]

The issue with dd is that if any read() fails, it skips the entry (64M) and doesn't write to the output, making the output file smaller than the input
file.

with conv=sync,noerror, it's better, but, still loosing a whole 64M block
at once is a bad thing.

That's why I think dd_rescue would be better.
<http://www.garloff.de/kurt/linux/ddrescue/>

If it still gets warm too fast, I've heard that storing the hard drive in a
freezer 24 hours may make it work again.
<http://geeksaresexy.blogspot.com/2006/01/freeze-your-hard-drive-to-recover-data.html>

If it crashes when dd or dd_rescue fails, it's possible to continue copying
later, from the point it failed.

--
André Gillibert



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read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

_______________________________________________
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https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/


--
Peter Keller Tel.: +44 (0)1223 353033 Global Phasing Ltd., Fax.: +44 (0)1223 366889
Sheraton House,
Castle Park,
Cambridge CB3 0AX
United Kingdom


--------------------------------------------------------------------------------


_______________________________________________
linux-lvm mailing list
linux-lvm redhat com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

_______________________________________________
linux-lvm mailing list
linux-lvm redhat com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

_______________________________________________
linux-lvm mailing list
linux-lvm redhat com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/


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