limited initial sync Bandwidth use

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eliripoll
Posts: 33
Joined: Sat Dec 08, 2012 8:19 pm
Location: United states

Wed Feb 26, 2014 4:12 am

Hello
I just got back around to do more testing on V8, and I came across something I was hoping you could help with. So when I created a new replicated/HA disk and went through the standard process/ wizard. normally I just check the SWS console and wait for it to say complete. but this time I went ahead and investigated metrics what I found was confusing. It seems like, over the sync channel I was only getting 100mb of use for each nic. even though they are a gig. My setup is two servers a dell 710 and a 1950, dedicated 2 port intel server nics 1gb. I have each port going through a different switch. and the storage are SSD's, jumbo frames are being used, and disk queue lengh was nil. Initially I thought maybe it something going on the network so I tested copying a large file and sure enough it saturate the line between the servers.

However the initial sync only uses 100mb, its interesting that the numbers are exactly 12.x MB which is almost exactly converted to 100mbits. the only reason I was getting 200mb transfer was because I was using 2 ports nics. Ive tried different switches with same result. Could you provide your thoughts on this is? is there something in the code that would throttle usage? again what I think is interesting/telling is that the transfer is using exactly 12.x MB. usually if its the network limiting down to 100mb you would see transfers of 10 or 11 MB because of TCP overhead not allowing for a perfect 12.x MB.

the 1st pic is regular SMB use
2nd 3rd pic is actual transfer number of sync and nic usage.
smb use
smb use
smbsws.png (12.23 KiB) Viewed 12634 times
nicuse.JPG
nicuse.JPG (15.87 KiB) Viewed 12634 times
initial sync
initial sync
swssync.JPG (9.62 KiB) Viewed 12633 times
Thanks Again
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Bohdan (staff)
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Joined: Wed May 23, 2007 12:58 pm

Wed Feb 26, 2014 10:21 am

Please zip and send us StarWind logs.
eliripoll
Posts: 33
Joined: Sat Dec 08, 2012 8:19 pm
Location: United states

Wed Feb 26, 2014 4:21 pm

Hi Bohdan,

Sure, Thanks for the reply, Ill start a new fresh sync and get those logs. but I probably wont be able to do it till tomorrow. Unfortunately the beta key I have expires tomorrow (midnight). has a new key been issued for beta testing yet?
eliripoll
Posts: 33
Joined: Sat Dec 08, 2012 8:19 pm
Location: United states

Sat Apr 05, 2014 9:57 pm

Hello, I know this is a month later ( been tied up with Project deadlines) but I was able to get back to the initial sync test. Since I needed to recreate one I figured I would download the latest build RC (had beta initially)
after starting initial the initial sync bandwidth doubled to two 20MB/s sessions (occasionally more) from a hard constant 12.7~8MB (capital B) Not sure why it could go faster as it was only syncing a completely empty 100gb thick disk, which should have just been copying a string of sequential 0's. But the destination was not SSD this time (15K sas) and the disk queue length was a steadily between 1-1.5 which is actually where I would probably want it. To note before when it was at 12MB/s the disk queue length didn't go past .5 to I knew there was available head room.

All in all I would say that the new RC has improved. I will include the logs from the primary system though.

Also I had an issue every time I created a replication partner where it would successfully get to the very end of the wizard for setting up the partner and target, disk. but at the very last step of starting the initial sync I would get an error saying "synchronization cannot be started" and to try manually. then I would try to start manually but no go. but if I stopped and restarted the starwind service on the Primary node. I can then go to the console on the partner and manually start the sync job.
synchronization not ready.JPG
synchronization not ready.JPG (22.09 KiB) Viewed 12470 times
eliripoll
Posts: 33
Joined: Sat Dec 08, 2012 8:19 pm
Location: United states

Sat Apr 05, 2014 10:00 pm

hmmm I tried uploading the log files but got extension not allowed, tried renaming it to txt and nothing. which way should I add them?
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anton (staff)
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Joined: Fri Jun 18, 2004 12:03 am
Location: British Virgin Islands
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Sat Apr 05, 2014 10:18 pm

Zip and send to support@starwindsoftware.com or write to the same e-mail asking for ftp account. Attaching to forum is a bad idea as we already have database ~3TB in size :)
eliripoll wrote:hmmm I tried uploading the log files but got extension not allowed, tried renaming it to txt and nothing. which way should I add them?
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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