When rsync has a lot of files to look through but not many to actually
transfer most of the work will be gathering information from the stat()
function call.  You can simulate just the stat call with: find /path
-type f -ls > /dev/null
You can run one then a few of those to see if your storage has issues
with lots of stats all at once.

Also, why -c aes128-ctr ?  If your OpenSSH is current then the default
of chacha20-poly1...@openssh.com is much faster.  If your systems have
AES-NI in the CPU then aes128-...@openssh.com is much faster.  If your
OpenSSH is too old for chacha to be the default then aes128-ctr was the
default anyway.

On 03/21/2018 09:49 AM, Jayce Piel via rsync wrote:
> 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
>> <mailto:rsync-requ...@lists.samba.org> a écrit :
>> *De: *Kevin Korb <k...@sanitarium.net <mailto:k...@sanitarium.net>>
>> *Objet: **Rép : Very slow to start sync with millions of directories
>> and files*
>> *Date: *19 mars 2018 à 15:33:31 UTC+1
>> *À: *rsync@lists.samba.org <mailto:rsync@lists.samba.org>
>> 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
>> -- 
>> ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,
>> Kevin KorbPhone:    (407) 252-6853
>> Systems AdministratorInternet:
>> FutureQuest, inc.ke...@futurequest.net
>> <mailto:ke...@futurequest.net>  (work)
>> Orlando, florida...@sanitarium.net <mailto:k...@sanitarium.net> (personal)
>> Web page:http://www.sanitarium.net/
>> PGP public key available on web site.
>> ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,
> -- 
> Jayce Piel   —    jayce.p...@gmail.com <mailto:jayce.p...@gmail.com>  --
>  0616762431
>    Responsable Informatique F.F.Tir

        Kevin Korb                      Phone:    (407) 252-6853
        Systems Administrator           Internet:
        FutureQuest, Inc.               ke...@futurequest.net  (work)
        Orlando, Florida                k...@sanitarium.net (personal)
        Web page:                       http://www.sanitarium.net/
        PGP public key available on web site.

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