[DRBD-user] 1x8disks or 2x4disks

Martin Spuetz martin at spuetz.net
Sun Feb 21 12:24:34 CET 2010

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


We are planning to install DRBD and Xen on two new servers.

We will buy the same hardware (32GB Ram, 8x SATA/SAS hard disks with
hardware raid controller). We will have four virtual machines per server
on a raid10 with 4 disks. In case of a failure 8 VMs on one server.

The virtual machines will be heavily I/O-intensive ((q)mail, file and

How can we achieve best performance?

a) One big lvm with master-master drbd and raid10 (8 disks) over 10gibt
Ethernet. Easy install and maintenance, fast sync. Is it really fast, if
two masters write simultaneously?

b) For the four virtual machines on each physical server a separated
drbd on top of a raid10 (each 4 disks). The servers would be connected
with one or two gigabit ports. There will be 4 disks on the master and 4
dedicated disks on the slave. Split brain shouldn't be a problem.

Maybe we need more disks but it would be the same architecture.


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