[DRBD-user] Re: DRBD and PostgreSQL

Federico Sevilla III jijo at free.net.ph
Wed Aug 31 06:42:25 CEST 2005

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

Hi Tom,
(cc DRBD Mailing List)

On Wed, Aug 31, 2005 at 04:08:30AM +0200, Thomas Uhl wrote:
> You mentioned that you are using or plan to use PostgreSQL and DRBD
> for a HA setup.
> What are your experiences since then?
> What are the limitations?
> Anything you would recommend?
> What are your database sizes?

I have deployed PostgreSQL on Heartbeat + DRBD at three locations for a
client of mine. They're a large retail outfit, and these PostgreSQL
servers handle the database that each store's point of sale terminals
query and append transaction information into in real time. Each store
has between 30 to 40 active point of sale terminals.

These are all two-way Xeon boxes with HyperThreading and 2GB RAM, and
run Debian GNU/Linux Sarge with the Linux 2.6 kernels and the XFS
filesystem (no LVM). They've all been running 24x7 since we deployed
them, with the oldest being in operation since May 2004 (some downtime
midway, during the store's off-hours of course, to migrate from Woody
with 2.4 kernels and the old DRBD to Sarge with 2. kernels and the new
DRBD after Sarge was released).

We've had a blast with PostgreSQL + Heartbeat + DRBD. We've added mon
into the fray, and it works wonders! It's saved us from a front-end
application error that clogged up PostgreSQL's maximum concurrent client
connections limit, and would otherwise have caused noticeable downtime
at the front-lines. It caused a ping-pong, but that gave us time to fix
the application, and aside from the server logs, the ping-pong wasn't

I'm also very happy with XFS on DRBD. Thankfully, we haven't been bitten
by any snags. Performance is awesome, and it Just Works (tm).
Maintainance work needed is also negligible.

Our raw database sizes (eg: by running a 'du' on the PostgreSQL data
directory) are about 7GB for each site.

 --> Jijo

Federico Sevilla III : jijo.free.net.ph : When we speak of free software
GNU/Linux Specialist : GnuPG 0x93B746BE : we refer to freedom, not price.

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