It is a Dell Powervault 700 server. I know, you don't support linux on this system, but I testet it also with a Poweredge 750 and also this servers have a iowait problem during the backup process.
I can not belive that the harddisk performance is the problem, the 10MBit network should be much more slow.
Have you check the network stat's? What kind of server is this? You may be over loading the system bus with 5 servers pushing data to this server at the same time.
sorry, my mistake, it's a Sell PowerVaul 745N NAS Server. I installed Linux Redhat on this machine because I need this backup solution only for Linux server.
You can try turning on the write cache in the RAID controller, however you will need to attach a APC to product again a power outage if you do so as there is no battery backup for the write cache on a power failure.
Yes, how do you turn on the write caching on this controller ?
I have the same problem with our first PE1800 SATA machine that uses the same controller but it runs Windows 2003.
Our write performance is absolutely dreadfull under RAID-5 but aside from having identified that the write caching is disabled, we have yet to find a solution for this performance problem.
I had a major problem with performance on our 745n when I first tried a large copy over the network. A couple things I have found out..
First, make sure you are not copying through mapped drive letters. Use UNC. There is a problem with windows copying large files through them.
Second, if you configure memory usage for programs instead of system cache it gives a pretty big performance boost. (This can be found in Control Panel/System/Advanced/Performance-Settings) The server was sometimes unresponsive durring copies until I switched this option. At first, the copy would fly until the memory was used up then it would slow down to a crawl once it hit the pagefile. With this enabled memory is unaffected and the copy is steady. I'm getting close to 600MB a minute now. (which is still not that great but usable)
NovaTrend
22 Posts
0
January 21st, 2005 12:00
It is a Dell Powervault 700 server. I know, you don't support linux on this system, but I testet it also with a Poweredge 750 and also this servers have a iowait problem during the backup process.
I can not belive that the harddisk performance is the problem, the 10MBit network should be much more slow.
Any other ideas?
Thanks
Michael
Eric BY
2 Intern
•
815 Posts
0
January 21st, 2005 12:00
NovaTrend
22 Posts
0
January 21st, 2005 12:00
Thanks
Michael
Eric BY
2 Intern
•
815 Posts
0
January 21st, 2005 12:00
Eric BY
2 Intern
•
815 Posts
0
January 21st, 2005 13:00
NovaTrend
22 Posts
0
February 5th, 2005 14:00
How can I turn on the write cache without to recreate the array? I did not find this option.
Thanks
Michael
Johan van de Ve
5 Posts
0
February 15th, 2005 06:00
Yes, how do you turn on the write caching on this controller ?
I have the same problem with our first PE1800 SATA machine that uses the same controller but it runs Windows 2003.
Our write performance is absolutely dreadfull under RAID-5 but aside from having identified that the write caching is disabled, we have yet to find a solution for this performance problem.
mattjc75
7 Posts
0
June 24th, 2005 20:00
First, make sure you are not copying through mapped drive letters. Use UNC. There is a problem with windows copying large files through them.
Second, if you configure memory usage for programs instead of system cache it gives a pretty big performance boost. (This can be found in Control Panel/System/Advanced/Performance-Settings) The server was sometimes unresponsive durring copies until I switched this option. At first, the copy would fly until the memory was used up then it would slow down to a crawl once it hit the pagefile. With this enabled memory is unaffected and the copy is steady. I'm getting close to 600MB a minute now. (which is still not that great but usable)
Hope this helps.