Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hello, I try to find that out. When I do dd on the raw devices (without drbd) I get speeds from approx. 40MB/sec. Not very fast but acceptable for the application. When I do tcpspray to test the network I get 80 till 100 MB/sec also okay. With drbd I get with recent kernels only 3 (three) MB/sec Just when the secondary side runs 2.6.5 its 10 times faster with drbd. I am pretty helpless what more to test. Each subsystem alone works okay. Just not together and I see no reason why. So I am looking for a why how to track the problem down. My test results gets even more confusing when I break the hardware raid5. When building a drbd device with each single disk the speed is fine. When putting linux software raid5 on top it goes unusable slow. Regards Torsten -----Ursprüngliche Nachricht----- Von: Francis I. Malolot [mailto:francis_m at proware.com.tw] Gesendet: Montag, 8. Mai 2006 09:38 An: drbd-user at lists.linbit.com; NEUMANN, TORSTEN Betreff: Re: [DRBD-user] Re: strange performance problems with drbd >the cisco switches between the two hosts don't allow that. Is it worth the >trouble with the network admins or does it explain the very slow drbd >performance with recent kernel versions? Try to crossover the link between the two host and do $ ifconfig eth0 MTU 6000 >The trouble is that I don't see any error messages. With other similiar drbd >setups ( drbd 0.7.17 SVN Revision: 2125M and kernel 22.214.171.124 ) on different >hosts I don't see that kind problems. There I got with the same network setup a >speed of approx. 80MB/sec when writing data with dd to the disk. Please check where's the bottleneck (scsi devices,etc) Kernel version should not be a problem with this. thanks, francism FingerPrint:3082 0CB4 0609 2A86 4886 F70D 0107 02A0 ----- Original Message ----- From: "Torsten Neumann" <torsten.neumann at dlh.de> To: <drbd-user at lists.linbit.com> Sent: Monday, May 08, 2006 3:28 PM Subject: [DRBD-user] Re: strange performance problems with drbd Francis I. Malolot <francis_m at ...> writes: > > please increase your MTU and feel the power of DRBD. > here we can pump at 125MB.... > the cisco switches between the two hosts don't allow that. Is it worth the trouble with the network admins or does it explain the very slow drbd performance with recent kernel versions? The trouble is that I don't see any error messages. With other similiar drbd setups ( drbd 0.7.17 SVN Revision: 2125M and kernel 126.96.36.199 ) on different hosts I don't see that kind problems. There I got with the same network setup a speed of approx. 80MB/sec when writing data with dd to the disk. Regards, Torsten > thanks, > francism _______________________________________________ drbd-user mailing list drbd-user at lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.