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<div style="color:rgb(31, 73, 125);">Just want to add on to one of the points Sven touched on regarding metadata HW. We have a modest SSD infrastructure for our metadata disks and we can scan 500M inodes in parallel in about 5 hours if my memory serves me right (and
I believe we could go faster if we really wanted to). I think having solid metadata disks (no pun intended) will really help with scan times. </div>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Helvetica","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Helvetica","sans-serif""> Sven Oehme<br>
<b>Sent:</b> 8/30/16, 7:25 PM<br>
<b>To:</b> gpfsug main discussion list<br>
<b>Subject:</b> Re: [gpfsug-discuss] *New* IBM Spectrum Protect Whitepaper "Petascale Data Protection"<o:p></o:p></span></p>
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<div dir="ltr">so lets start with some simple questions.
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<div>when you say mmbackup takes ages, what version of gpfs code are you running ? </div>
<div>how do you execute the mmbackup command ? exact parameters would be useful . </div>
<div>what HW are you using for the metadata disks ? </div>
<div>how much capacity (df -h) and how many inodes (df -i) do you have in the filesystem you try to backup ?</div>
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<div>sven</div>
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<div class="gmail_quote">On Tue, Aug 30, 2016 at 3:02 PM, Lukas Hejtmanek <span dir="ltr">
<<a href="mailto:xhejtman@ics.muni.cz">xhejtman@ics.muni.cz</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex">
Hello,<br>
<br>
On Mon, Aug 29, 2016 at 09:20:46AM +0200, Frank Kraemer wrote:<br>
> Find the paper here:<br>
><br>
> <a href="https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/Tivoli%20Storage%20Manager/page/Petascale%20Data%20Protection" rel="noreferrer" target="_BLANK">
https://www.ibm.com/<wbr>developerworks/community/<wbr>wikis/home?lang=en#!/wiki/<wbr>Tivoli%20Storage%20Manager/<wbr>page/Petascale%20Data%<wbr>20Protection</a><br>
<br>
thank you for the paper, I appreciate it.<br>
<br>
However, I wonder whether it could be extended a little. As it has the title<br>
Petascale Data Protection, I think that in Peta scale, you have to deal with<br>
millions (well rather hundreds of millions) of files you store in and this is<br>
something where TSM does not scale well.<br>
<br>
Could you give some hints:<br>
<br>
On the backup site:<br>
mmbackup takes ages for:<br>
a) scan (try to scan 500M files even in parallel)<br>
b) backup - what if 10 % of files get changed - backup process can be blocked<br>
several days as mmbackup cannot run in several instances on the same file<br>
system, so you have to wait until one run of mmbackup finishes. How long could<br>
it take at petascale?<br>
<br>
On the restore site:<br>
how can I restore e.g. 40 millions of file efficiently? dsmc restore '/path/*'<br>
runs into serious troubles after say 20M files (maybe wrong internal<br>
structures used), however, scanning 1000 more files takes several minutes<br>
resulting the dsmc restore never reaches that 40M files.<br>
<br>
using filelists the situation is even worse. I run dsmc restore -filelist<br>
with a filelist consisting of 2.4M files. Running for *two* days without<br>
restoring even a single file. dsmc is consuming 100 % CPU.<br>
<br>
So any hints addressing these issues with really large number of files would<br>
be even more appreciated.<br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
Lukáš Hejtmánek<br>
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