[OpenAFS] Support for large volumes

Mauricio Villarroel villarroel.mauricio@gmail.com
Mon, 31 Aug 2009 18:57:21 -0400


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Hi all,

In our research group at MIT, we use AFS for different purposes, such as:
students' home directories, thesis repositories, etc. So far it is working
without major problems. Our current setup is:

* AFS version 1.4.11
* Both server and clients are running Fedora 11 x86_64, which basically
means kernels 2.6.29.x

We installed OpenAFS using the 64bit rpms provided from
http://openafs.org/release/1.4.11/index-fedora-11.html    , the installation
was very easy with no major incidents.

Lately, we are exploring the option of using AFS to manage our research
data, which consist of large datasets of patient information from different
hospital archives.

I read that since version 1.4.8 , AFS supports partitions larger that 2TB,
so I think that solves part of our problems. The issue comes when I want to
use volumes larger that 2TB, there are many reasons that prevent me to split
a given volume into smaller volumes of ~2TB max.

As an example: let's assume the name of my cell is "cell_name" and one of
the volumes that I want to create will be mounted under
"hospital1/waveformdb/icu". The following odd scenarios occur:

Setting the volume quota to 1TB with a command similar to:

       $ fs setquota -path /afs/cell_name/hospital1/waveformdb/icu -max
1073741824

gives me the correct results, I can check that with:

       $ fs examine /afs/cell_name/hospital1/waveformdb/icu
        ***
        Current disk quota is 1073741824
        ***

The problem starts when I set the quota limit to 2TB, it gives me an
incorrect "negative" quota size:

          Current disk quota is -2147483648

When I set the quota limit to 3TB, it gives me:

          Current disk quota is -1073741824

And when I set the quota limit to 4TB, it gives me:

           Current disk quota is unlimited

If I want to set the max quota limit to 6TB, it gives me :

           Current disk quota is -2147483648

What is the limit for a volume?. I read online that one possible source of
the limitation comes from some data structure that are using 32bits "ints"
and changing them would mean changing the AFS communication protocol?, if
this is the case, is there a plan to increase it?

Best,

Mauro

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Hi all,<br><br>In our research group at MIT, we use AFS for different purpo=
ses, such as: students&#39; home directories, thesis repositories, etc. So =
far it is working without major problems. Our current setup is:<br><br>* AF=
S version 1.4.11<br>
* Both server and clients are running Fedora 11 x86_64, which basically mea=
ns kernels 2.6.29.x<br><br>We installed OpenAFS using the 64bit rpms provid=
ed from <a href=3D"http://openafs.org/release/1.4.11/index-fedora-11.html">=
http://openafs.org/release/1.4.11/index-fedora-11.html</a>=A0=A0=A0 , the i=
nstallation was very easy with no major incidents.<br>
<br>Lately, we are exploring the option of using  AFS to manage our researc=
h data, which consist of large datasets of patient information from differe=
nt hospital archives.<br><br>I read that since version 1.4.8 , AFS supports=
 partitions larger that 2TB, so I think that solves part of our problems. T=
he issue comes when I want to use volumes larger that 2TB, there are many r=
easons that prevent me to split a given volume into smaller volumes of ~2TB=
 max. <br>
<br>As an example: let&#39;s assume the name of my cell is &quot;cell_name&=
quot; and one of the volumes that I want to create will be mounted under &q=
uot;hospital1/waveformdb/icu&quot;. The following odd scenarios occur:<br>
<br>Setting the volume quota to 1TB with a command similar to:<br><br>=A0=
=A0=A0=A0=A0=A0 $ fs setquota -path /afs/cell_name/hospital1/waveformdb/icu=
 -max 1073741824<br><br>gives me the correct results, I can check that with=
:<br><br>=A0=A0=A0=A0=A0=A0 $ fs examine  /afs/cell_name/hospital1/waveform=
db/icu<br>
=A0=A0=A0=A0=A0=A0=A0 ***<br>=A0=A0=A0=A0=A0=A0=A0 Current disk quota is 10=
73741824<br>=A0=A0=A0=A0=A0=A0=A0 ***<br><br>The problem starts when I set =
the quota limit to 2TB, it gives me an incorrect &quot;negative&quot; quota=
 size: <br><br>=A0=A0=A0=A0=A0=A0=A0=A0=A0 Current disk quota is -214748364=
8<br>
<br>When I set the quota limit to 3TB, it gives me:<br><br>=A0=A0=A0=A0=A0=
=A0=A0=A0=A0
Current disk quota is -1073741824<br><br>And when I set the quota limit to =
4TB, it gives me:<br><br>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 Current disk quota =
is unlimited<br><br>If I want to set the max quota limit to 6TB, it gives m=
e :<br><br>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 Current disk quota is -2147483648=
<br>
<br>What is the limit for a volume?. I read online that one possible source=
 of the limitation comes from some data structure that are using 32bits &qu=
ot;ints&quot; and changing them would mean changing the AFS communication p=
rotocol?, if this is the case, is there a plan to increase it?<br>
<br>Best,<br><br>Mauro<br>

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