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

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?

If yes, as a temporary workaround I can patch vdsmd to run multipath -r when e.g. monitoring the storage domain.

>> 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