[DRBD-user] mounting ro from secondary machines

Omer Faruk Sen omer at faruk.net
Thu Apr 13 12:50:11 CEST 2006

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


Is it possible to mount drbd on slave machines as read-only. I have tried
it but got following errors:

[root at clu2 /]# mount /dev/drbd0 /mnt
/dev/drbd0: Input/output error
mount: block device /dev/drbd0 is write-protected, mounting read-only
/dev/drbd0: Input/output error
mount: /dev/drbd0 already mounted or /mnt busy

I have 2 drbd machines (clu1 and clu2) .. Clu1 mount drbd0 and writes it
but at the same time I want to mount it on clu2. I have found out that
there is nbd and enbd projects but these mounts directly (in my situation)
clu1's shared partition.

I want to setup slave mysql servers that mounts drbd partiotion as
read-only with caching disabled. Thus I will offload my master mysql
server from replication burden and I am living problems about replication
WRITE operations on mysql Master can be so high that replication on slaves
lag. I thought using drbd I will always have the same data as master and
replication will be handled in kernel not on application..

Best Regards.

Omer Faruk Sen

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