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Hi Vimal,<br>
I have a simple suggestion. I think it would be great to first
test FS-Cache with the NFS and Samba servers in GlusterFS. I think
just proving these technologies work well together without any
issues would be great start. I am not sure if this information is
already available with GlusterFS specifically, but it still would be
great to gain this experience.<br>
Once you have enough experience with FS-Cache and standard
protocols for GlusterFS, then you can battle FUSE. <br>
<br>
Just my $0.02. Either way it should be fun and I look forward to
your results :-).<br>
<br>
- Luis<br>
<br>
<div class="moz-cite-prefix">On 09/03/2014 03:25 AM, Vimal A R
wrote:<br>
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<div><span>David / Dan / Anand,</span></div>
<div style="color: rgb(0, 0, 0); font-size: 10.6667px;
font-family: Helvetica Neue-Light,Helvetica Neue
Light,Helvetica Neue,Helvetica,Arial,Lucida Grande,Sans-Serif;
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<span></span></div>
<div style="color: rgb(0, 0, 0); font-size: 10.6667px;
font-family: Helvetica Neue-Light,Helvetica Neue
Light,Helvetica Neue,Helvetica,Arial,Lucida Grande,Sans-Serif;
background-color: transparent; font-style: normal;"><span>Thank
you for all the suggestions. I will make a note of the
points, and will get back here if I have anything to report
or doubts.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 10.6667px;
font-family: Helvetica Neue-Light,Helvetica Neue
Light,Helvetica Neue,Helvetica,Arial,Lucida Grande,Sans-Serif;
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<span></span></div>
<div style="color: rgb(0, 0, 0); font-size: 10.6667px;
font-family: Helvetica Neue-Light,Helvetica Neue
Light,Helvetica Neue,Helvetica,Arial,Lucida Grande,Sans-Serif;
background-color: transparent; font-style: normal;"><span>Thanks
a lot,</span></div>
<div style="color: rgb(0, 0, 0); font-size: 10.6667px;
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font-family: Helvetica Neue-Light,Helvetica Neue
Light,Helvetica Neue,Helvetica,Arial,Lucida Grande,Sans-Serif;
background-color: transparent; font-style: normal;"><span>Vimal<br>
</span></div>
<div class="qtdSeparateBR"><br>
<br>
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<div style="font-family: times new roman, new york, times,
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<div dir="ltr"> <font size="2" face="Arial"> On Tuesday,
2 September 2014 8:50 PM, Anand Avati
<a class="moz-txt-link-rfc2396E" href="mailto:avati@gluster.org"><avati@gluster.org></a> wrote:<br>
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<br>
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<div class="yiv9695472571gmail_quote">On Mon,
Sep 1, 2014 at 6:07 AM, Vimal A R <span
dir="ltr"><<a moz-do-not-send="true"
rel="nofollow" shape="rect"
ymailto="mailto:arvimal@yahoo.in"
target="_blank"
href="mailto:arvimal@yahoo.in">arvimal@yahoo.in</a>></span>
wrote:<br clear="none">
<blockquote class="yiv9695472571gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex;">Hello
fuse-devel / fs-cache / gluster-devel lists,<br
clear="none">
<br clear="none">
I would like to propose the idea of
implementing FS-Cache support in the fuse
kernel module, which I am planning to do as
part of my UG university course. This
proposal is by no means final, since I have
just started to look into this.<br
clear="none">
<br clear="none">
There are several user-space filesystems
which are based on the FUSE kernel module.
As of now, if I understand correct, the only
networked filesystems having FS-Cache
support are NFS and AFS.<br clear="none">
<br clear="none">
Implementing support hooks for fs-cache in
the fuse module would provide networked
filesystems such as GlusterFS the benefit
of a client-side caching mechanism, which
should decrease the access times.<br
clear="none">
</blockquote>
<div>
<br clear="none">
</div>
<div>If you are planning to test this with
GlusterFS, note that one of the first
challenges would be to have persistent
filehandles in FUSE. While GlusterFS has a
notion of a persistent handle (GFID, 128bit)
which is constant across clients and
remounts, the FUSE kernel module is
presented a transient LONG (64/32 bit) which
is specific to the mount instance (actually,
the address of the userspace inode_t within
glusterfs process - allows for constant time
filehandle resolution).</div>
<div><br clear="none">
</div>
<div>This would be a challenge with any FUSE
based filesystem which has persistent
filehandles larger than 64bit.</div>
<div><br clear="none">
</div>
<div>Thanks</div>
<div class="yiv9695472571yqt8000248471"
id="yiv9695472571yqtfd18423">
<div><br clear="none">
</div>
<div> </div>
<blockquote class="yiv9695472571gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex;">
When enabled, FS-Cache would maintain a
virtual indexing tree to cache the data or
object-types per network FS. Indices in
the tree are used by FS-Cache to find
objects faster. The tree or index
structure under the main network FS index
depends on the filesystem. Cookies are
used to represent the indices, the pages
etc..<br clear="none">
<br clear="none">
The tree structure would be as following:<br
clear="none">
<br clear="none">
a) The virtual index tree maintained by
fs-cache would look like:<br clear="none">
<br clear="none">
* FS-Cache master index -> The
network-filesystem indice (NFS/AFS etc..)
-> per-share indices -> File-handle
indices -> Page indices<br clear="none">
<br clear="none">
b) In case of FUSE-based filesystems, the
tree would be similar to :<br clear="none">
<br clear="none">
* FS-Cache master index -> FUSE indice
-> Per FS indices -> file-handle
indices -> page indices.<br
clear="none">
<br clear="none">
c) In case of FUSE based filesystems as
GlusterFS, the tree would as :<br
clear="none">
<br clear="none">
* FS-Cache master index -> FUSE indice
(fuse.glusterfs) -> GlusterFS volume ID
(a UUID exists for each volume) - >
GlusterFS file-handle indices (based on
the GFID of a file) -> page indices.<br
clear="none">
<br clear="none">
The idea is to enable FUSE to work with
the FS-Cache network filesystem API, which
is documented at '<a
moz-do-not-send="true" rel="nofollow"
shape="rect" target="_blank"
href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/netfs-api.txt">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/netfs-api.txt</a>'.<br
clear="none">
<br clear="none">
The implementation of FS-Cache support in
NFS can be taken as a guideline to
understand and start off.<br clear="none">
<br clear="none">
I will reply to this mail with any other
updates that would come up whilst pursuing
this further. I request any sort of
feedback/suggestions, ideas, any pitfalls
etc.. that can help in taking this
further.<br clear="none">
<br clear="none">
Thank you,<br clear="none">
<br clear="none">
Vimal<br clear="none">
<br clear="none">
References:<br clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/fscache.txt">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/fscache.txt</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/netfs-api.txt">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/netfs-api.txt</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/object.txt">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/caching/object.txt</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="http://people.redhat.com/dhowells/fscache/FS-Cache.pdf">http://people.redhat.com/dhowells/fscache/FS-Cache.pdf</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="http://people.redhat.com/steved/fscache/docs/HOWTO.txt">http://people.redhat.com/steved/fscache/docs/HOWTO.txt</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="https://en.wikipedia.org/wiki/CacheFS">https://en.wikipedia.org/wiki/CacheFS</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="https://lwn.net/Articles/160122/">https://lwn.net/Articles/160122/</a><br
clear="none">
* <a moz-do-not-send="true"
rel="nofollow" shape="rect"
target="_blank"
href="http://www.linux-mag.com/id/7378/">http://www.linux-mag.com/id/7378/</a><br
clear="none">
_______________________________________________<br clear="none">
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