<html><head></head><body>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.<br>
<br>
<br>
Regards,<br>
Neil<br><br><div class="gmail_quote">On 30 June 2015 11:59:08 BST, Federico Alves <venefax@gmail.com> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div dir="ltr"><div class="gmail_default" style="font-size:small">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?<br /><br /></div></div><div class="gmail_extra"><br /><div class="gmail_quote">On Tue, Jun 30, 2015 at 2:03 AM, Fajar A. Nugraha <span dir="ltr"><<a href="mailto:list@fajar.net" target="_blank">list@fajar.net</a>></span> wrote:<br /><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On Tue, Jun 30, 2015 at 7:16 AM, Federico Alves <<a href="mailto:venefax@gmail.com">venefax@gmail.com</a>> wrote:<br />
> I need to create 500 identical containers, but after the first one, I don´t<br />
> want to repeat the same file 500 times. The disk is formatted ext4. What<br />
> should be the best type of format or partition that would be 100% sparse,<br />
> i.e., it would never repeat the same information.<br />
<br />
</div></div>That's not the definition of sparse: <a href="https://en.wikipedia.org/wiki/Sparse_file" rel="noreferrer" target="_blank">https://en.wikipedia.org/wiki/Sparse_file</a><br />
<br />
If you want to "create a container one time and clone it for the other<br />
499", then you can create container_1 container using<br />
snapshot-cabapble backingstore (e.g. zfs), then run "lxc-clone -s<br />
container_1 container_2". This should create container 2 using<br />
snapshot/clone feature of the storage (at least this works on zfs,<br />
should work on btrfs as well) so that the only additional space that<br />
will be used is only for changed files/blocks (e.g. container config,<br />
/etc/hosts, and so on). Note that as the containers get used, the<br />
changed files will increase (e.g. logs, database files), and those<br />
changed files will use additional space.<br />
<br />
See also "man lxc-clone":<br />
Creates a new container as a clone of an existing container. Two types<br />
of clones are supported: copy and snapshot. A copy clone copies the<br />
root filessytem from the original container to the new. A snapshot<br />
filesystem uses the backing store's snapshot functionality to create a<br />
very small copy-on-write snapshot of the original container.<br />
Snapshot clones require the new container backing store to support<br />
snapshotting. Currently this includes only aufs, btrfs, lvm, overlayfs<br />
and zfs. LVM devices do not support snapshots of snapshots.<br />
<br />
<br />
If you REALLY want a system that "would never repeat the same<br />
information", then you'd need dedup-capable storage. zfs can do that,<br />
but it implies high overhead (e.g. much higher memory requirements<br />
compared to normal, and needs a fast L2ARC), and should NOT be used<br />
unless you REALLY know what you're doing.<br />
<span class="HOEnZb"><font color="#888888"><br />
--<br />
Fajar<br />
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<p style="margin-top: 2.5em; margin-bottom: 1em; border-bottom: 1px solid #000"></p><pre class="k9mail"><hr /><br />lxc-users mailing list<br />lxc-users@lists.linuxcontainers.org<br /><a href="http://lists.linuxcontainers.org/listinfo/lxc-users">http://lists.linuxcontainers.org/listinfo/lxc-users</a></pre></blockquote></div><br>
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