El 11/08/2015 a las 06:37 a.m., Götz Reinicke - IT Koordinator escribió: > Hi, > > i have two servers, connected to to the lan by 10Gb with 10Gb and DAS > hardware raid. > > Each system con read and write locally or to the 10G iscsi by more than > 200 MB/s. > > Now I have to transfer backups form A to B and doing this with rsync > always stuck at +- 48-50MB/s no matter which options, compressions, > encryption etc I use. Even the plain default rsync is at that 50 Mb limit. > > coyp by scp goes up to 200 MB/s. > > Copy from and to my workstation with scp from or to both servers is at > 1Gb limit (so +- 100 MB/s) > > > Why is rsync stuck at +- 50 MB/s ? Any suggestions hints ... rsync is not a like a copy, it checks from both sides that the file to copy is not the same on the other side. Copying something is straight forward, it dont wait to a remote check of the files metadata or attributes (last modification, permissions, etc). Access disk time could explain this... I dont know how you are using rsync... if you are using the network protocol or a nfs mount. check this also, if the rsync is using a single tcp connection for each file, and you have a lot of small files, the problem could be the slow start congestion algorithm of tcp (scp uses a single conection to copy, im sure of that. i dont know how rsync protocol works) Also, if you have a lot of small files, it will take a lot of access time (disk seek time) for each to fetch this information and then start the copy. See if you can do a iostat on each server doing a scp and a rsync to see the disk usage diference... if you find that you have a large queue on disk when using rsync, thats the problem... I hope this helps to point the way to solve your problem. Saludos, Juan.