On 13:43 Wed 19 Oct , Zdenek Kabelac wrote: > Dne 19.10.2016 v 12:53 Daniel Armbruster napsal(a): > > Hi List, > > > > I'm looking for a device-mapper target driver giving me the possibility to > > track/log WRITE requests. The idea is to track those WRITE requests within a > > Bitmap e.g. 1:LV-EXTEND (for LVM2). I read already the device-mapper > > documentation under > > > > https://www.kernel.org/doc/Documentation/device-mapper/ > > > > but didn't find an appropriate module which would suite my needs. > > > > Is there any work happening on this to leverage? Any kind of help is > > appreciated. > > > > Many thanks in advance. > > > Hi > > > Not exactly sure what you are trying to do but 2 things to look at: > > Maybe 'dmstats' with it's region logic may cover your 'wanted' operation. > > The kernel dm target to check would be 'era' which keeps trace > of written blocks. > > Regards > > Zdenek > > > Hi Zdenek, thanks for your help. I'm trying to implement a synchronization tool which performs backups in an intelligent way. Since using a snapshot is only partly an option (the snapshot could fill up and the snapshot_autoextend_* practicality of LVM2 isn't stable enough under heavy load) I was thinking about the possibility of an additional device which keeps trace of written blocks. To improve performance I aim at reducing the data throughput. That's why I was thinking about a Bitmap e.g. 1:LV-EXTEND. I thought already about the DM statistics module. Is there any performance impact when collecting statistics for a given volume (except of the additionally allocated memory used)? Is there a possibility to quantify it? As well I'm going to have a closer look at the era module. Many thanks for the hint. Regards, Daniel -- gpg --keyserver keys.gnupg.net --recv-key EF60F5CC -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
