[DRBD-user] Transfer rates

Helmut Wollmersdorfer helmut.wollmersdorfer at gmx.at
Thu Jun 24 18:32:17 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Daniel Khan schrieb:

> Could someone provide some figures which real troughput can be expected 
> with drbd and 1000Mbit.


> 0: cs:SyncingAll st:Primary/Secondary ns:20803700 nr:0 dw:0 dr:20803860 
> pe:15 ua:0
>         [>...................] sync'ed:  3.8% (305724/317546)M
>         finish: 2:59:12h speed: 29,274 (28,962) K/sec

That's near the maximum speed of yor disks - isn't it?
At sync you have only drbd in a very efficient mode, the disks and the 
network. You have only read on primary disk, write on secondary disk.

> NFS gives me only 120Mbit if I test with dd.

Now you add dd and NFS to the above "time consumers", plus write on 
primary disk. This definitely cannot be faster than sync at maximum 
possible speed, it should be slower. Here it's ~50% of sync, not a 
dramatic difference.

> So something might be wrong here....

- check, that you can exclude network, storage, cpu as reason
- review your drbd and NFS config, try to fine tune it

Helmut Wollmersdorfer

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