[linux-lvm] pvmove speed

[Roy Sigurd Karlsbakk <roy@karlsbakk.net>]

Hi all

I'm doing pvmove of some rather large volumes from a Dell Equallogic system to Dell Compellent. Both are connected on iSCSI to vmware and the guest OS seems to do this well, but it's slow. I get around 50MB/s at most, even though the Equallogic is connected at 4x1Gbps and the Compellent is on 10Gbps. Without multipath, this should give me 100MB/s or so, but then, I get half of that. Interestingly, the "utilisation" reported by munin shows me a 100% in total of the two devices compared, as in https://karlsbakk.net/tmp/pvmove-dev-util.png

Any idea why this utilisation is so high, and what I can do to speed this thing up? I'm at a 14 days mark to move these 40TiB or so, and I'd like to reduce it if possible. The backend is obviously not a problem here.

Vennlig hilsen / Best regards

roy
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Roy Sigurd Karlsbakk
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