| Message ID | orbnp6uofj.fsf@free.home (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 21 Oct 2014, Alexandre Oliva wrote: > On Aug 27, 2013, Sage Weil <sage@inktank.com> wrote: > > > Finally, eventually we should make this do a checkpoint on the mons too. > > We can add the osd snapping back in first, but before this can/should > > really be used the mons need to be snapshotted as well. Probably that's > > just adding in a snapshot() method to MonitorStore.h and doing either a > > leveldb snap or making a full copy of store.db... I forget what leveldb is > > capable of here. > > I suppose it might be a bit too late for Giant, but I finally got 'round > to implementing this. I attach the patch that implements it, to be > applied on top of the updated version of the patch I posted before, also > attached. > > I have a backport to Firefly too, if there's interest. > > I have tested both methods: btrfs snapshotting of store.db (I've > manually turned store.db into a btrfs subvolume), and creating a new db > with all (prefix,key,value) triples. I'm undecided about inserting > multiple transaction commits for the latter case; the mon mem use grew > up a lot as it was, and in a few tests the snapshotting ran twice, but > in the end a dump of all the data in the database created by btrfs > snapshotting was identical to that created by explicit copying. So, the > former is preferred, since it's so incredibly more efficient. I also > considered hardlinking all files in store.db into a separate tree, but I > didn't like the idea of coding that in C+-, :-) and I figured it might > not work with other db backends, and maybe even not be guaranteed to > work with leveldb. It's probably not worth much more effort. This looks pretty reasonable! I think we definitely need to limit the size of the transaction when doing the snap. The attached patch seems to try to do it all in one go, which is not going to work for large clusters. Either re-use an existing tunable like the sync chunk size or add a new one? Thanks! sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
reinstate ceph cluster_snap support From: Alexandre Oliva <oliva@gnu.org> This patch brings back and updates (for dumpling) the code originally introduced to support “ceph osd cluster_snap <snap>”, that was disabled and partially removed before cuttlefish. Some minimal testing appears to indicate this even works: the modified mon actually generated an osdmap with the cluster_snap request, and starting a modified osd that was down and letting it catch up caused the osd to take the requested snapshot. I see no reason why it wouldn't have taken it if it was up and running, so... Why was this feature disabled in the first place? Signed-off-by: Alexandre Oliva <oliva@gnu.org> --- src/mon/MonCommands.h | 6 ++++-- src/mon/OSDMonitor.cc | 11 +++++++---- src/osd/OSD.cc | 8 ++++++++ 3 files changed, 19 insertions(+), 6 deletions(-) diff --git a/src/mon/MonCommands.h b/src/mon/MonCommands.h index d702615..8f468f4 100644 --- a/src/mon/MonCommands.h +++ b/src/mon/MonCommands.h @@ -499,8 +499,10 @@ COMMAND("osd set " \ COMMAND("osd unset " \ "name=key,type=CephChoices,strings=pause|noup|nodown|noout|noin|nobackfill|norecover|noscrub|nodeep-scrub|notieragent", \ "unset <key>", "osd", "rw", "cli,rest") -COMMAND("osd cluster_snap", "take cluster snapshot (disabled)", \ - "osd", "r", "") +COMMAND("osd cluster_snap " \ + "name=snap,type=CephString", \ + "take cluster snapshot", \ + "osd", "r", "cli") COMMAND("osd down " \ "type=CephString,name=ids,n=N", \ "set osd(s) <id> [<id>...] down", "osd", "rw", "cli,rest") diff --git a/src/mon/OSDMonitor.cc b/src/mon/OSDMonitor.cc index bfcc09e..b237846 100644 --- a/src/mon/OSDMonitor.cc +++ b/src/mon/OSDMonitor.cc @@ -4766,10 +4766,13 @@ bool OSDMonitor::prepare_command_impl(MMonCommand *m, } } else if (prefix == "osd cluster_snap") { - // ** DISABLE THIS FOR NOW ** - ss << "cluster snapshot currently disabled (broken implementation)"; - // ** DISABLE THIS FOR NOW ** - + string snap; + cmd_getval(g_ceph_context, cmdmap, "snap", snap); + pending_inc.cluster_snapshot = snap; + ss << "creating cluster snap " << snap; + getline(ss, rs); + wait_for_finished_proposal(new Monitor::C_Command(mon, m, 0, rs, get_last_committed())); + return true; } else if (prefix == "osd down" || prefix == "osd out" || prefix == "osd in" || diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc index f2f5df5..eb4f246 100644 --- a/src/osd/OSD.cc +++ b/src/osd/OSD.cc @@ -6310,6 +6310,14 @@ void OSD::handle_osd_map(MOSDMap *m) } } + string cluster_snap = newmap->get_cluster_snapshot(); + if (cluster_snap.length()) { + dout(0) << "creating cluster snapshot '" << cluster_snap << "'" << dendl; + int r = store->snapshot(cluster_snap); + if (r) + dout(0) << "failed to create cluster snapshot: " << cpp_strerror(r) << dendl; + } + osdmap = newmap; superblock.current_epoch = cur;