Re: speeding up zfs send | recv (update)

On Feb 22, 2023 at 7:28 PM, Sysadmin Lists <sysadmin.lists@mailfence.com> wrote:

On Feb 22, 2023 at 1:43 PM, Freddie Cash <fjwcash@gmail.com> wrote:
[Sorry for top part, GMail sucks for replies.]

If this is a LAN or private WAN where you trust the network, piping the send stream through netcat will remove ssh from the equation.

That's what we switched to using once it became almost impossible to get the "none" cipher working with ssh on FreeBSD.

We use ssh to connect to the remote server and enable a netcat listener on port X, then pipe the send through netcat to the remote system on port X. That way it's logged and uses ssh for authentication.

We easily saturate gigabit links between our ZFS systems using netcat.

Cheers,
Freddie

Typos due to smartphone keyboard.

On Wed., Feb. 22, 2023, 1:31 p.m. Miroslav Lachman, <000.fbsd@quip.cz> wrote:

On 22/02/2023 22:08, mike tancsa wrote:
> On 2/22/2023 4:03 PM, Miroslav Lachman wrote:
>> Interresting numbers. I think I am the only one who get best speed 
>> with chacha20-poly1305@openssh.com
>>
>>
>> It seems the speed of SSH is limited by single core performance which 
>> is very poor on this machine (Intel(R) Pentium(R) Dual  CPU E2160). 
>> Even if CPU has 50% idle, ssh runs on 99.8% of single core.
> 
> The CPU I have has
> aesni0: <AES-CBC,AES-CCM,AES-GCM,AES-ICM,AES-XTS> on motherboard
> 
> which probably helps.

That explains it
aesni0: No AES or SHA support.

>> I know there were some HPN patches to ssh, beside that is there any 
>> option I can try to use less CPU?
>>
>> I will play with cpuset to pin ssh on one core and everything else on 
>> the other core.
> 
> It looks like you are running into a CPU bottleneck TBH

Yes. Pinning on cores with cpuset helps a bit (about +3MiB/s) but 
without some tweaks on ssh I will not gain more speed :(

Thank you for your help!

Miroslav Lachman

You could pipe the stream through an encrypting program before piping to
netcat, then decrypt on the recieving end.

$ zfs send | crypt | netcat ipaddr 2222
$ netcat -vl 2222 | crypt | zfs recv

I don't know if zfs can handle that, but worth a try.

$ man crypt
    The enigma utility, also known as crypt is a very simple encryption
     program, working on a “secret-key” basis.  It operates as a filter, i.e.,
     it encrypts or decrypts a stream of data from standard input, and writes
     the result to standard output.  Since its operation is fully symmetrical,
     feeding the encrypted data stream again through the engine (using the
     same secret key) will decrypt it.

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Seems to work:

# zfs create zroot/test
# mount -t zfs zroot/test /mnt/test
# date > /mnt/test/testfile
# zfsnap snapshot -p testsend- zroot/test
# zfs list -t snap zroot/test
NAME ...
zroot/test@testsend-2023-02-22_19.46.15--1m ...

# nc -l 2222 | crypt | zfs recv zroot/newtest
Enter key:

# zfs send zroot/test@testsend-2023-02-22_19.46.15--1m | crypt | nc -w 5 localhost 2222
Enter key:

# zfs list zroot/newtest
NAME            USED  AVAIL     REFER  MOUNTPOINT
zroot/newtest    96K  70.7G       96K  none

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