most likely, you ovestrain your NAS with disk random IOPs. furthermore, iSCSI is an additional throttle here, making things worse.
your issue is probably centered around metadata reads/latency...
have a look on IO-Wait on the server/nas side...
regards
roland
Gesendet: Mittwoch, 21. März 2018 um 14:49 Uhr
Von: "Jayce Piel via rsync" <rsync@lists.samba.org>
An: rsync@lists.samba.org
Betreff: rsync very very slow with multiple instances at the same time.
Von: "Jayce Piel via rsync" <rsync@lists.samba.org>
An: rsync@lists.samba.org
Betreff: rsync very very slow with multiple instances at the same time.
I create a new thread, because the issue is not really the same, but i copy here the thread that made me jump into the list.
My issue is not really that it waits before starting copying, but a general performance issue, specially when there are multiple rsync running at the same time.
Here is my situation :
I have multiple clients (around 20) with users and i want to rsync their home dirs with my server to keep a copy of their local files.
On the server, files are hosted on a iSCSI volume (on a Thecus RAID) where i never had any performance issue before.
When there is only one client, i have no real performance issues. In a few minutes, even with a very large number of files (some users have up to ), the sync is done if there are not too many changed files.
But when there are 3 or more rsync at the same time, all rsync become very very slow and can take a few hours to complete.
Here are my options :
/usr/local/bin/rsync3 --rsync-path=/usr/local/bin/rsync3 -aHXxvE --stats --numeric-ids --delete-excluded --delete-before --human-readable —rsh="ssh -T -c aes128-ctr -o Compression=no -x" -z --skip-compress=gz/bz2/jpg/jpeg/ogg/mp3/mp4/mov/avi/vmdk/vmem --inplace --chmod=u+w --timeout=60 —exclude=‘Caches' —exclude=‘SyncService' —exclude=‘.FileSync' —exclude=‘IMAP*' —exclude=‘.Trash' —exclude='Saved Application State' —exclude='Autosave Information' --exclude-from=/Users/pabittan/.UserSync/exclude-list --max-size=1000M /Users/pabittan/ xserve.local.fftir:./
Here is the version i use (self compiled) :
$ /usr/local/bin/rsync3 --version
rsync version 3.1.2-jsp protocol version 31
Copyright (C) 1996-2015 by Andrew Tridgell, Wayne Davison, and others.
Web site: http://rsync.samba.org/
Capabilities:
64-bit files, 64-bit inums, 64-bit timestamps, 64-bit long ints,
socketpairs, hardlinks, symlinks, IPv6, batchfiles, inplace,
append, ACLs, xattrs, iconv, symtimes, no prealloc, file-flags
I had to put in place a sort of queue to not allow more than 4 simultaneous rsync to be sure they run at least once a day each. Even limiting to 4 rsync makes some wait hours before starting a backup.
I’m open to any help to improve perfs. (i have put my whole script calling rsync on github : https://github.com/jpiel/UserSync )
PS:
I checked, CPU is not under pressure, each rsync instance use between 2 and 5% CPU. The whole CPU usage 30%.
I also checked network, and it’s not either an issue.
Disk usage doesn’t seem to be at a high load either… (peak at 300 IO/sec)
Le 20 mars 2018 à 13:00, rsync-requ...@lists.samba.org a écrit :De: Kevin Korb <k...@sanitarium.net>Objet: Rép : Very slow to start sync with millions of directories and filesDate: 19 mars 2018 à 15:33:31 UTC+1
The performance of rsync with a huge number of files is greatly
determined by every option you are using. So, what is your whole
command line?
On 03/19/2018 09:05 AM, Bráulio Bhavamitra via rsync wrote:Hi all,
I'm using rsync 3 to copy all files from one disk to another. The files
were writen by Minio, an S3 compatible opensource backend.
The number of files is dozens of millions, almost each of them within
its own directory.
Rsync takes a long time, when not several hours, to even start syncing
files. I already see a few reasons:
- it first create all directories to put files in, that could be done
along with the sync
- it needs to generate the list of all files before starting, and cannot
start syncing and keep the list generation in a different thread.
Cheers,
bráulio
--
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Kevin Korb Phone: (407) 252-6853
Systems Administrator Internet:
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Responsable Informatique F.F.Tir
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