ZimbraDesktop2 B1 - very slow sync.

[kevindods]

Hi

Just checking if people are experiencing any marked differences in the beta install across different machines.

I had a Karmic install on a 2GB, 2.8GHz desktop that synced 3GB in a few hours. I have a Netbook with Karmic 1GB+ 1.6 Atom that took 3 days for the same mailbox and takes 10mins to sync a few messages.

I know the hardware is distinctly uneven but using the same wired network connections and 8Mb/s internet connection I would not expect such a difference. With ZD1 it was fine and much more comparable but having killed and deleted ZD1 entirely and installed ZD2 things are very much slower.

As it is a beta I expect problems but I thought I would enquire and see if the problem I am experiencing is unique and perhaps take comment on where to start digging!

K

[jmhe]

the overall performance also has to do with disk IO speed.

[kevindods]

Yes, guess so, but the difference was almost negligible when using ZD1 and the disks are SATA and SSD. 2-3hrs vs 2+days seems a little extreme for around 3GB

3GB in 48hrs is a little over 128Kb/s That would be a seriously slow drive even on SSD! ;-)

[jmhe]

in 2.0, we switched to sqlite from derby for database. since sqlite does not have transaction logging (only redo logging), it's more sensitive to slow i/o.

one experiment you can try is to turn on sqlite debug logging, see how long does it take to do one transaction.

in your zd user data directory, you should find this file:

conf\log4j.properties

add this line to the end of the file and restart zd service:

log4j.logger.zimbra.sqltrace=DEBUG

you will see more log written to log\zdesktop.log. feel free to post them here if you are not sure how to interpret sql tracing.

Originally Posted by kevindods

Yes, guess so, but the difference was almost negligible when using ZD1 and the disks are SATA and SSD. 2-3hrs vs 2+days seems a little extreme for around 3GB

3GB in 48hrs is a little over 128Kb/s That would be a seriously slow drive even on SSD! ;-)

[kevindods]

Thanks, I have done so and grabbed the last bit of the log for review. On average the initial sync of emails are running at about 25-30 per minute as per the leaner logs. Add in some attachments and mess and the 52,200 odd email messages look like 30 hours or so which is a little shorter than the 2days it actually took. The desktop was running at 20 emails per sec for the same mailbox on the same connection and wired network.

These trace logs seem to show about the same sort of time but I dont know if the traces look unusual or unreasonable - SQL traces are not my native tongue ;-)

NB I use sqlite for some music libraries and they seem to update about as well on the netbook as on the desktop - library is about 44GB and 10K items.

[tfr]

SQLite db lookup operations look perfect - 1-20 ms each but write commits are slow - several hundred ms. Do you happen to have one of the old MLC SSD drives that cause severe stuttering on writes? If it is not one of the newest generations with updated controllers, then the sync writes in sqlite could have terrible performance. Wiping out an old zimbra install and re-syncing with 2.0 on a JMicron controller could put an SSD into slow performance mode until you reformat it.

[kevindods]

Thanks for getting back to me. Its the 32GB SSD on the Eee 1000, probably not the fastest and probably jmicron ;-)

Not clear on what you mean by slow performance until reformatted? Presume you don't mean an ext2/3/4 reformat?

I read that sqlite can have the pragma/sync turned off but not sure where that would figure in this nor where that might be set with ZD configs.

There are plenty of netbooks that would benefit from ZD2 and so it may be good to find a way to get them to run smoother....

[jmhe]

looks like it's a known issue that Eee 1000 32GB SSD is very slow on write (jkkmobile: Asus Eee PC SSD read and write tests: Eee 1000 vs Eee 901).

you may want to contact their tech support or search on the net for workarounds.

[tfr]

That would definitely do it. I literally just bought a new SSD this morning as a Newegg special because my SSD had a jmicron controller causing multi-second Windows 7 delays. It clears up after you reformat the filesystem, but that gets old every couple of months. There are several apps on the net that will help tweak Windows registry settings that help a bit, but eventually you must reformat or buy a new drive. 1GB of memory on a notebook also exacerbates the problem because you swap out memory more often.

However, I will look into adding a special config option to disable mandatory disk syncs for sqlite for users willing to run in an insecure mode. If you don't keep local data in local folders, that won't be a serious problem because you can always reset & resync

[tfr]

https://bugzilla.zimbra.com/show_bug.cgi?id=45122 has been filed and will be in the next next beta. I will have details on what to edit in localconfig.xml later if you could please test and let me know if any options help