NAS to NAS or RTRR

[Elvar]

Hello, I have two TS-EC1679U-RP's at different sites. One is housing 100+ gigs of archived email stored in Maildir format. The other unit is being used to back up data from the first unit. My question is, what is the difference between NAS to NAS replication vs. RTRR? Do they use different protocols? Is one better than the other for syncing Maildir data? Is it better to use NAS to NAS when using two QNAP devices? I can't seem to find any documentation stating what scenarios are better for which replication method. Any guidance would be greatly appreciated.


Kind regards,
Elvar

[pwilson]

Hello, I have two TS-EC1679U-RP's at different sites. One is housing 100+ gigs of archived email stored in Maildir format. The other unit is being used to back up data from the first unit. My question is, what is the difference between NAS to NAS replication vs. RTRR? Do they use different protocols? Is one better than the other for syncing Maildir data? Is it better to use NAS to NAS when using two QNAP devices? I can't seem to find any documentation stating what scenarios are better for which replication method. Any guidance would be greatly appreciated.


Kind regards,
Elvar

Both methods use "RTRR". The NAS-to-NAS option is simply optimized from doing so between two "QNAP" NAS devices.

[Elvar]

Both methods use "RTRR". The NAS-to-NAS option is simply optimized from doing so between two "QNAP" NAS devices.

So in our case where both devices are QNAP devices, I assume I should switch to the NAS to NAS option for optimization purposes?

Thanks for the reply!

[xavierh]

Both methods use "RTRR". The NAS-to-NAS option is simply optimized from doing so between two "QNAP" NAS devices.

So in our case where both devices are QNAP devices, I assume I should switch to the NAS to NAS option for optimization purposes?

Thanks for the reply!

keep in mind that for NAS-to_NAS to work your all your files must be inside [directory_1] in NAS_A so that it can be replicated to [directory_1] in NAS_B. in other words, let say you have a directory called media and inside that directory you have several directories (movies, pictures, music) then NAS-to-NAS will work as you will only have to sent the job using the "media" directory on NAS_A to replicate to media directory in NAS_B.

if on the other hand you have separate directories. then you will either have to set separate jobs for each one, or then use RRTR and set one job with up to 5 folder pairs

so in summary
NAS-to-NAS: one folder pair per job
RRTR: up to to 5 folder pairs per job

[P3R]

keep in mind that for NAS-to_NAS to work your all your files must be inside [directory_1] in NAS_A so that it can be replicated to [directory_1] in NAS_B.

It doesn't have to be the same shared folder (or any other folder) on the source and destination.

[P3R]

Both methods use "RTRR".

No that is not correct!

NAS to NAS uses rsync (port 873 by default) and RTRR uses the rtrr (port 8899 by default) or the ftp protocol (port 20/21 by default). RTRR over ftp have some functional limitations compared to rtrr.

NAS to NAS should really be read QNAP to QNAP as that is the intention of it. The Rsync tab should be used with any non-Qnap rsync server as destination.

NAS to NAS works block based while RTRR works on full file level only.

In my experience rsync is almost always preferable; it is available on all major operating systems, it is very lean over slow connections, it doesn't necessarily need to synchronize complete files when something have changed.

The only time I would prefer RTRR would be if (near) real time remote replication or ftp protocol is a requirement. YMMV and one or the other could be better in specific applications. I have no experience with "100+ gigs of archived email stored in Maildir format". The largest replicated file structures I regularly (every night) use rsync on are:

• 451.98 GB with 41427 files in it
• 185 GB with 74356 files in it
• 82.2 GB with 80847 files in it
• 7.53 GB with 107538 files in it

[doktornotor]

The only time I would prefer RTRR would be if (near) real time remote replication or ftp protocol is a requirement. YMMV and one or the other could be better in specific applications. I have no experience with "100+ gigs of archived email stored in Maildir format".

Well, 100+ gigs of maildirs is probably tens and tens of millions of small files and a sure recipe for disaster with rsync. Doubt it's ever gonna finish the initial sync.

[reinob]

The only time I would prefer RTRR would be if (near) real time remote replication or ftp protocol is a requirement. YMMV and one or the other could be better in specific applications. I have no experience with "100+ gigs of archived email stored in Maildir format".

Well, 100+ gigs of maildirs is probably tens and tens of millions of small files and a sure recipe for disaster with rsync. Doubt it's ever gonna finish the initial sync.

I'd do the initial sync by hand, packing/piping everything with tar.

[doktornotor]

I'd do the initial sync by hand, packing/piping everything with tar.

Yeah, some pre-seeding would be definitely required.

[xavierh]

keep in mind that for NAS-to_NAS to work your all your files must be inside [directory_1] in NAS_A so that it can be replicated to [directory_1] in NAS_B.

It doesn't have to be the same shared folder (or any other folder) on the source and destination.

you are right P3R it doe snot have to be the same folder. i just did not want to confuse things further...

[kherr4377]

I get half the speed with NAS/NAS compared to RTRR/FTP. I backup every day and sometimes that means 200GB+ in new/changed files. With N/N I get 45~MB and with RTRR I get 95~MB. It's a no brainer ...... This is backing up one TS-469L to another.

[Elvar]

Both methods use "RTRR".

No that is not correct!

NAS to NAS works block based while RTRR works on full file level only.

[*]7.53 GB with 107538 files in it[/list]

This is good to know and what I was hoping was the case. Thanks!

[Elvar]

The only time I would prefer RTRR would be if (near) real time remote replication or ftp protocol is a requirement. YMMV and one or the other could be better in specific applications. I have no experience with "100+ gigs of archived email stored in Maildir format".

Well, 100+ gigs of maildirs is probably tens and tens of millions of small files and a sure recipe for disaster with rsync. Doubt it's ever gonna finish the initial sync.

It ended up taking about 2-3 days via 50mbit uplinks. Unfortunately I had to change RTRR to scheduled RTRR in order to make use of file deletions due to the nature of Maildir changing the locations of files from ./new to ./cur etc.

[P3R]

Unfortunately I had to change RTRR to scheduled RTRR in order to make use of file deletions due to the nature of Maildir changing the locations of files from ./new to ./cur etc.

If you by this mean that you had to change from real time RTRR because of this then you'd probably wan't to know that real time RTRR does replicate file deletions also. It's only not shown correctly in the admin gui.

[JohnJoe123]

I need some help on

"NAS to NAS works block based while RTRR works on full file level only."

Could someone explain the significance of this statement to me? Does it have a large impact on the amount of data exchanged?
I have two TS-653Pro's and doing initial setup. I am trying to understand options to limit data traffic and if remote replication over the internet is going to work. I have only a DSL connection (2MB up, 10MBS down) to work with. Have numerous 1 gig email files (*.pst format) that have a date change every time you open them up, even if you change nothing.