Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Mon, Dec 08, 2008 at 02:17:50PM -0800, Ben Chobot wrote: > 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. :) put an other way: if you write a 1 MByte file to a DRBD, and fsync it, and your replication bandwidth is 200 kByte/sec, it will take five seconds. if that was 200 kBit/sec, well, it will take 40 seconds. and that does not take latency into account at all. you should definetely mount noatime. and probably rethink your needs. > 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. >> >> _______________________________________________ >> drbd-user mailing list >> drbd-user at lists.linbit.com >> http://lists.linbit.com/mailman/listinfo/drbd-user >> > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed