[pve-devel] [PATCH] Increases the dd read/write speed when migrating LVM disks. This should bring LVM migration speed up to match that of rsyncing qcows.

[Michael Rasmussen]

On Wed, 24 Aug 2016 18:59:29 +0200 (CEST)
Dietmar Maurer <dietmar at proxmox.com> wrote:

> > Seems 64k is a good value.  
> 
> What value do you get with 4K?
> 
mir at esx1:~$ time dd if=/tmp/big.file bs=4K |ssh esx2 "dd of=big.file bs=4k"
262144+0 records in
262144+0 records out
1073741824 bytes (1.1 GB) copied, 3.94589 s, 272 MB/s
262144+0 records in
262144+0 records out
1073741824 bytes (1.1 GB) copied, 3.82583 s, 281 MB/s

real	0m3.953s
user	0m2.072s
sys	0m2.212s
mir at esx1:~$ time dd if=/tmp/big.file bs=8K |ssh esx2 "dd of=big.file bs=8k"
131072+0 records in
131072+0 records out
1073741824 bytes (1.1 GB) copied, 3.69495 s, 291 MB/s
131072+0 records in
131072+0 records out
1073741824 bytes (1.1 GB) copied, 3.38373 s, 317 MB/s

real	0m3.704s
user	0m1.964s
sys	0m2.208s


-- 
Hilsen/Regards
Michael Rasmussen

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