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'm trying to optimize write performances on a primary/primary drbd cluster. The nodes are connected directly with a dedicated gigabit network. To get rid of filesystem perfs, I'm adressing the drbd ressource directly. Here's what dd gives me (I'm using one big chuck to get rid of latency) : # dd if=/dev/zero of=/dev/drbd0 bs=512M count=1 oflag=direct 1+0 enregistrements lus 1+0 enregistrements écrits 536870912 octets (537 MB) copiés, 30,3065 seconde, 17,7 MB/s Now, I disconnect the ressource : # drbdadm disconnect r0 And I have very better perfs : # dd if=/dev/zero of=/dev/drbd0 bs=512M count=1 oflag=direct 1+0 enregistrements lus 1+0 enregistrements écrits 536870912 octets (537 MB) copiés, 8,6145 seconde, 62,3 MB/s When syncing, I get : finish: 3:07:23 speed: 61,240 (55,320) K/sec Which seems around the real performance. The version is : version: 8.0.16 (api:86/proto:86) Do you have any clue about what is giving me this 3.5 factor ? What other information can I give you ? Thanks for your help, Julien Escario