[lxc-users] Best backing store for 500 containers

[Neil Greenwood]

The comment was that zfs doing active de-duplication across all the containers' file systems has too high an overhead. As Fajar said in his latest reply, he is using zfs for his containers.


Regards,
Neil

On 30 June 2015 11:59:08 BST, Federico Alves <venefax at gmail.com> wrote:
>So, if zfs has too high overhead, the ideal backing store should be
>aufs,
>btrfs, lvm or overlayfs? My host is Fedora 22, are they all supported?
>
>
>On Tue, Jun 30, 2015 at 2:03 AM, Fajar A. Nugraha <list at fajar.net>
>wrote:
>
>> On Tue, Jun 30, 2015 at 7:16 AM, Federico Alves <venefax at gmail.com>
>wrote:
>> > I need to create 500 identical containers, but after the first one,
>I
>> don´t
>> > want to repeat the same file 500 times. The disk is formatted ext4.
>What
>> > should be the best type of format or partition that would be 100%
>sparse,
>> > i.e., it would never repeat  the same information.
>>
>> That's not the definition of sparse:
>> https://en.wikipedia.org/wiki/Sparse_file
>>
>> If you want to "create a container one time and clone it for the
>other
>> 499", then you can create container_1 container using
>> snapshot-cabapble backingstore (e.g. zfs), then run "lxc-clone -s
>> container_1 container_2". This should create container 2 using
>> snapshot/clone feature of the storage (at least this works on zfs,
>> should work on btrfs as well) so that the only additional space that
>> will be used is only for changed files/blocks (e.g. container config,
>> /etc/hosts, and so on). Note that as the containers get used, the
>> changed files will increase (e.g. logs, database files), and those
>> changed files will use additional space.
>>
>> See also "man lxc-clone":
>> Creates a new container as a clone of an existing container. Two
>types
>> of clones are supported: copy and snapshot. A copy clone copies the
>> root filessytem from the original container to the new. A snapshot
>> filesystem uses the backing store's snapshot functionality to create
>a
>>  very small  copy-on-write snapshot of the original container.
>> Snapshot clones require the new container backing store to support
>> snapshotting. Currently this includes only aufs, btrfs, lvm,
>overlayfs
>> and zfs. LVM devices do not support snapshots of snapshots.
>>
>>
>> If you REALLY want a system that "would never repeat  the same
>> information", then you'd need dedup-capable storage. zfs can do that,
>> but it implies high overhead (e.g. much higher memory requirements
>> compared to normal, and needs a fast L2ARC), and should NOT be used
>> unless you REALLY know what you're doing.
>>
>> --
>> Fajar
>> _______________________________________________
>> lxc-users mailing list
>> lxc-users at lists.linuxcontainers.org
>> http://lists.linuxcontainers.org/listinfo/lxc-users
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>lxc-users mailing list
>lxc-users at lists.linuxcontainers.org
>http://lists.linuxcontainers.org/listinfo/lxc-users

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linuxcontainers.org/pipermail/lxc-users/attachments/20150630/33413711/attachment.html>