From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: In-Reply-To: <51DDAB43.7070001@redhat.com> References: <731d217f00b6d8f6c16a75cbe167baed.squirrel@mail.mohawksoft.com> <51DAF9AF.900@redhat.com> <51DB0CF6.7070400@redhat.com> <51DD1A8E.9080702@redhat.com> <741f708c46ffac16eeab39629823d5c2.squirrel@mail.mohawksoft.com> <51DDAB43.7070001@redhat.com> Date: Wed, 10 Jul 2013 16:12:32 -0400 From: markw@mohawksoft.com MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [linux-lvm] Snapshots of snapshots are not supported yet 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" To: Zdenek Kabelac Cc: LVM general discussion and development > Dne 10.7.2013 16:45, markw@mohawksoft.com napsal(a): > As I said - btrfs has some kind of functionality you are looking for, > Or you may start to help with lvm project... > (Or thin-provisioning tools in this case) > > Zdenek That link you sent was good, I am looking in to it, it may provide a large amount of help. One last thing.... :-) Now imagine this: create disk0 Activity on disk0 Take a snapshot disk0 -> disk0_snap0 Activity on disk0 take a snapshot disk0 -> disk0_snap1 (We will now use the differential between snap1 and snap0 to represent what needs to be backed up from snap1) This leaves us with something that looks like this: disk0 --> disk0_snap0 -> disk0_snap1 Will we need to remap the parentage of disk0_snap0 so it looks something like this? disk0 -> disk0_snap1 -> disk0_snap0 (Is this possible with dmsetup?) Or could we have many (order of hundreds or thousands) of snaps directly on disk0 and not impact performance?