From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <511A2E14.6060907@redhat.com> Date: Tue, 12 Feb 2013 12:57:08 +0100 From: Marian Csontos MIME-Version: 1.0 References: In-Reply-To: Content-Transfer-Encoding: 7bit Subject: Re: [linux-lvm] Slow boot with large number of thin snapshots Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: LVM general discussion and development Cc: Andres Toomsalu On 02/07/2013 01:42 PM, Andres Toomsalu wrote: > Hi, > > We have experienced a situation where we are left with large number > of thin snapshots (around 500) and snapshot removal wont work anymore > (we suspect a lock-up situation caused by trying to remove thin > snapshots that is still mounted - thou its not verified yet - just a > speculation). The only path to recover seems to be disabling all > thin volumes from fstab and booting into single-user mode - where > lvremove -f usually succeeds on these thin snapshots. But LVM init > and lvremove take a huge amount of time with large number of > snapshots - initial LVM activation is going on about 6-8 minutes at > least and every lvremove takes ca 20-50 sec - depending on snapshot > count left. After snapshots are removed thin volumes can be enabled > again and fsck-ed and resuming normal operations. Hello Andres, could you provide the following information: Which version of lvm? Is lvmetad used? grep lvmetad /etc/lvm/lvm.conf pgrep lvmetad RHEL6.3 version of lvmetad had a serious performance issue with many [thin] snapshots, which should be solved in the latest release (lvm2-2.02.98) Could you check the memory usage while the command is running? Also there were a high memory usage problems fixed in the recent version. -- Marian > > Althou we are not yet sure what is causing the lockup - so that > snapshots cant be removed anymore without reboot - its also > problematic that with large numbers of snapshots all LVM device > operations are dead slow. I hope this issue can be addressed somehow > in the future. > > Kind regards, > > > > _______________________________________________ linux-lvm mailing > list linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO > at http://tldp.org/HOWTO/LVM-HOWTO/