[DRBD-user] Bandwidth limit?

Ben Chobot bench at silentmedia.com
Mon Dec 8 23:17:50 CET 2008

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


My understanding is that the minimum bandwidth DRBD needs depends entirely 
on how fast you're writing data and how much latency you're will to put up 
with/how big your buffers are. If you're okay with absurdly long writes 
and don't write very much/often, you could run it over a modem.

Or so goes my understanding. :)

On Mon, 8 Dec 2008, Lorenzo Milesi wrote:

> Hi all...
>
> I already wrote before on the list about the solution I have at a
> customer running DRBD8+OCFS2 on two remote sites connected via VPN.
> The situation is resumed as:
> SITE A: Dual Core 2GHz Pentium, 1Gb ram, 1 SATA hdd for /, 3 SATA hdd in
> software raid5, DRBD on /dev/md0.
> SITE B: Quad Core 2.4HGz Pentium, 2Gb ram, 3 SATA HDD in software raid5,
> DRBD on /dev/md1.
>
> The two sites are connected using two ADSL, with TWO bonded VPN.
>
> Both machines run Debian Etch fully updated, kernel 2.6.26-bpo.1-686 SMP
> with deadline scheduler, DRBD 8.0.13, OCFS2 1.4.1-1.
> The shared data partition is 187G, 30 of which used.
>
> What would be the lowest needed bandwidth for DRBD to work correctly?
> Actually we have around 200/400kB, but we experience very slow
> operations on the filesystem, like for normal directory listing or rsync
> backups. In OCFS2 they told me it could be a bandwidth problem, partly
> due to FS and partly to the block device. What are DRBD's minimum
> requirements?
>
> Thank you.
> -- 
> Lorenzo Milesi - lorenzo.milesi at yetopen.it
>
> YetOpen S.r.l. - http://www.yetopen.it/
> C.so E. Filiberto, 74 23900 Lecco - ITALY -
> Tel 0341 220 205 - Fax 178 607 8199
>
> GPG/PGP Key-Id: 0xE704E230 - http://keyserver.linux.it
>
> -------- D.Lgs. 196/2003 --------
>
> Si avverte che tutte le informazioni contenute in questo messaggio sono
> riservate ed a uso esclusivo del destinatario. Nel caso in cui questo
> messaggio Le fosse pervenuto per errore, La invitiamo ad eliminarlo
> senza copiarlo, a non inoltrarlo a terzi e ad avvertirci non appena
> possibile.
> Grazie.
>
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