Re: [Users] SD Disk's Logical Volume not visible/activated on some nodes

From: "Nir Soffer" <nsoffer(a)redhat.com&gt; To: "Boyan Tabakov" <blade(a)alslayer.net&gt; Cc: users(a)ovirt.org, "Zdenek Kabelac" <zkabelac(a)redhat.com&gt; Sent: Monday, March 3, 2014 9:39:47 PM Subject: Re: [Users] SD Disk's Logical Volume not visible/activated on some nodes Hi Zdenek, can you look into this strange incident? When user creates a disk on one host (create a new lv), the lv is not seen on another host in the cluster. Calling multipath -r cause the new lv to appear on the other host. Finally, lvs tell us that vg_mda_free is zero - maybe unrelated, but unusual. ----- Original Message ----- > From: "Boyan Tabakov" <blade(a)alslayer.net&gt; > To: "Nir Soffer" <nsoffer(a)redhat.com&gt; > Cc: users(a)ovirt.org > Sent: Monday, March 3, 2014 9:51:05 AM > Subject: Re: [Users] SD Disk's Logical Volume not visible/activated on some > nodes > >>>>>> Consequently, when creating/booting > >>>>>> a VM with the said disk attached, the VM fails to start on host2, > >>>>>> because host2 can't see the LV. Similarly, if the VM is started on > >>>>>> host1, it fails to migrate to host2. Extract from host2 log is in > >>>>>> the > >>>>>> end. The LV in question is 6b35673e-7062-4716-a6c8-d5bf72fe3280. > >>>>>> > >>>>>> As far as I could track quickly the vdsm code, there is only call to > >>>>>> lvs > >>>>>> and not to lvscan or lvchange so the host2 LVM doesn't fully > >>>>>> refresh. > > > > lvs should see any change on the shared storage. > > > >>>>>> The only workaround so far has been to restart VDSM on host2, which > >>>>>> makes it refresh all LVM data properly. > > > > When vdsm starts, it calls multipath -r, which ensure that we see all > > physical volumes. > > > >>>>>> > >>>>>> When is host2 supposed to pick up any newly created LVs in the SD > >>>>>> VG? > >>>>>> Any suggestions where the problem might be? > >>>>> > >>>>> When you create a new lv on the shared storage, the new lv should be > >>>>> visible on the other host. Lets start by verifying that you do see > >>>>> the new lv after a disk was created. > >>>>> > >>>>> Try this: > >>>>> > >>>>> 1. Create a new disk, and check the disk uuid in the engine ui > >>>>> 2. On another machine, run this command: > >>>>> > >>>>> lvs -o vg_name,lv_name,tags > >>>>> > >>>>> You can identify the new lv using tags, which should contain the new > >>>>> disk > >>>>> uuid. > >>>>> > >>>>> If you don't see the new lv from the other host, please provide > >>>>> /var/log/messages > >>>>> and /var/log/sanlock.log. > >>>> > >>>> Just tried that. The disk is not visible on the non-SPM node. > >>> > >>> This means that storage is not accessible from this host. > >> > >> Generally, the storage seems accessible ok. For example, if I restart > >> the vdsmd, all volumes get picked up correctly (become visible in lvs > >> output and VMs can be started with them). > > > > Lests repeat this test, but now, if you do not see the new lv, please > > run: > > > > multipath -r > > > > And report the results. > > > > Running multipath -r helped and the disk was properly picked up by the > second host. > > Is running multipath -r safe while host is not in maintenance mode? It should be safe, vdsm uses in some cases. > If yes, as a temporary workaround I can patch vdsmd to run multipath -r > when e.g. monitoring the storage domain. I suggested running multipath as debugging aid; normally this is not needed. You should see lv on the shared storage without running multipath. Zdenek, can you explain this? > >> One warning that I keep seeing in vdsm logs on both nodes is this: > >> > >> Thread-1617881::WARNING::2014-02-24 > >> 16:57:50,627::sp::1553::Storage.StoragePool::(getInfo) VG > >> 3307f6fa-dd58-43db-ab23-b1fb299006c7's metadata size exceeded > >> critical size: mdasize=134217728 mdafree=0 > > > > Can you share the output of the command bellow? > > > > lvs -o > > uuid,name,attr,size,free,extent_size,extent_count,free_count,tags,vg_mda_size,vg_mda_free,lv_count,pv_count,pv_name > > Here's the output for both hosts. > > host1: > [root@host1 ~]# lvs -o > uuid,name,attr,size,vg_free,vg_extent_size,vg_extent_count,vg_free_count,tags,vg_mda_size,vg_mda_free,lv_count,pv_count > LV UUID LV > Attr LSize VFree Ext #Ext Free LV Tags > > VMdaSize VMdaFree #LV #PV > jGEpVm-oPW8-XyxI-l2yi-YF4X-qteQ-dm8SqL > 3d362bf2-20f4-438d-9ba9-486bd2e8cedf -wi-ao--- 2.00g 114.62g 128.00m > 1596 917 > IU_0227da98-34b2-4b0c-b083-d42e7b760036,MD_5,PU_f4231952-76c5-4764-9c8b-ac73492ac465 > 128.00m 0 13 2 This looks wrong - your vg_mda_free is zero - as vdsm complains. Zdenek, how can we debug this further?