For the people who don’t already have DRBD 8.4.3 deployed: here’s another good reason — Performance. Continue reading
DRBD 8.4.3: faster than ever
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Tag Archives: performance
Mirrored SAN vs. DRBD
Every now and then we get asked “why not simply use a mirrored SAN instead of DRBD”? This post shows some important differences. Continue reading
“read-balancing” with 8.4.1+
DRBD 8.4.1 introduces a new feature: read-balancing, which is configured in the disk section of the configuration file(s). This feature enables DRBD to balance read requests between the Primary/Secondary nodes. Continue reading
Trust, but verify
DRBD tries to ensure data integrity across different computers, and it’s quite good at it.
But, as per the old saying Trust, But Verify1 it might be a good idea to periodically test whether the nodes really have identical data, similar to the checks that are2 done for RAID sets. Continue reading
DRBD and the sync rate controller (8.3.9 and above)
The sync-rate controller is used for controlling the used bandwidth during resynchronization (not normal replication); it runs in the SyncTarget state, ie. on the (inconsistent) receiver side. Continue reading
DRBD causes too much CPU-load
The TL;DR version: don’t use data-integrity-alg in a production setup. Continue reading
“al-extents” explained
There is quite a bit of confusion about the DRBD configuration value al-extents (activity log extents), so here’s another shot at explaining it. Continue reading
Make the kernel start write-out earlier
Similar to the recent post about setting the vm.min_free_kbytes value there’s another sysctl that might improve the behaviour: the dirty ratio. Continue reading