Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi list, I have a question about the feasibility of a dual primary setup over two VDSL WAN links. I already searched the list and I found similar question, but without having a definitive conclusion. My goal is to have a shared fileserver over two distant offices, using DRBD to create the illusion of a single block devices. I plan to use GFS2 (or OCFS) filesystem, exporting it to users (on both side) via Samaba shares. Please note that: 1) both server are CentOS 6.x x86_64 machines, with DRBD packages provided by ElRepo (DRBD 8.4.x) 2) the main and remote offices are connected with relatively fast (~100 Mb/s) but high latency (+30 ms RTT) VDSL links 3) write speed should be as high as possible My current understanding (correct me if wrong) is that: 1) to not impair write speed, I should use protocol A 2) GFS2 (or any cluster filesystem) is quite sensitive to latency, so some operation (eg: metadata mangling, locking, reading an alredy remote-opened files) will be slowed down anyway 3) all will work (more or less) fine unless the WAN/VPN goes down. It is the "WAN failed" scenario that puzzle me. Let me do some questions: 1) at the block/device level, will both hosts (being both primary nodes) continue to accept writes? If so, will they end in a "split brain" scenario, right? 2) will the higher level filesystem (eg: GFS2) will block until the remote connection is re-established? 3) what will happens at connection recover? I understand that I can try myself (and I am going to do it, indeed), however I can only test on a fast LAN, not on a (relatively) slow WAN link. Thank you all. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti at assyoma.it - info at assyoma.it GPG public key ID: FF5F32A8