<span style=" font-size:10pt;font-family:Helvetica">Have you tried looking

at Spectrum Archive setting instead of Spectrum Scale?</span>

<br>

<br><span style=" font-size:10pt;font-family:Helvetica">You can set both

the size of the "stub file" that remains behind when a file is

migrated, and also the amount of data which would need to be read before

a recall is triggered. This might catch enough of your recall storms...

or at least help!</span>

<br>

<br><span style=" font-size:10pt;font-family:Helvetica"><b><u>IBM Spectrum

Archive Enterprise Edition V1.3.0: Installation and Configuration Guide</u></b></span>

<br><a href=http://www.redbooks.ibm.com/abstracts/sg248333.html?Open><span style=" font-size:10pt;color:blue;font-family:Helvetica">http://www.redbooks.ibm.com/abstracts/sg248333.html?Open</span></a>

<br>

<br><span style=" font-size:10pt;font-family:Helvetica"><i>7.14.3 Read

Starts Recalls: Early trigger for recalling a migrated file</i></span>

<br><span style=" font-size:10pt;font-family:Helvetica">IBM Spectrum Archive

EE can define a stub size for migrated files so that the stub size initial</span>

<br><span style=" font-size:10pt;font-family:Helvetica">bytes of a migrated

file are kept on disk while the entire file is migrated to tape. The migrated</span>

<br><span style=" font-size:10pt;font-family:Helvetica">file bytes that

are kept on the disk are called the <span style=" font-size:11pt;font-family:TimesNewRoman,Italic">stub<span style=" font-size:10pt;font-family:Helvetica">.

Reading from the stub does not trigger</span>

<br><span style=" font-size:10pt;font-family:Helvetica">a recall of the

rest of the file. After the file is read beyond the stub, the recall is

triggered. The</span>

<br><span style=" font-size:10pt;font-family:Helvetica">recall might take

a long time while the entire file is read from tape because a tape mount</span>

<br><span style=" font-size:10pt;font-family:Helvetica">might be required,

and it takes time to position the tape before data can be recalled from

tape.</span>

<br><span style=" font-size:10pt;font-family:Helvetica">When Read Start

Recalls (RSR) is enabled for a file, the first read from the stub file

triggers a</span>

<br><span style=" font-size:10pt;font-family:Helvetica">recall of the complete

file in the background (asynchronous). Reads from the stubs are still</span>

<br><span style=" font-size:10pt;font-family:Helvetica">possible while

the rest of the file is being recalled. After the rest of the file is recalled

to disks,</span>

<br><span style=" font-size:10pt;font-family:Helvetica">reads from any

file part are possible.</span>

<br><span style=" font-size:10pt;font-family:Helvetica">With the Preview

Size (PS) value, a preview size can be set to define the initial file part

size</span>

<br><span style=" font-size:10pt;font-family:Helvetica">for which any reads

from the resident file part does not trigger a recall. Typically, the PS

value</span>

<br><span style=" font-size:10pt;font-family:Helvetica">is large enough

to see whether a recall of the rest of the file is required without triggering

a</span>

<br><span style=" font-size:10pt;font-family:Helvetica">recall for reading

from every stub. This process is important to prevent unintended massive</span>

<br><span style=" font-size:10pt;font-family:Helvetica">recalls. The PS

value can be set only smaller than or equal to the stub size.</span>

<br><span style=" font-size:10pt;font-family:Helvetica">This feature is

useful, for example, when playing migrated video files. While the initial

stub</span>

<br><span style=" font-size:10pt;font-family:Helvetica">size part of a

video file is played, the rest of the video file can be recalled to prevent

a pause</span>

<br><span style=" font-size:10pt;font-family:Helvetica">when it plays beyond

the stub size. You must set the stub size and preview size to be large</span>

<br><span style=" font-size:10pt;font-family:Helvetica">enough to buffer

the time that is required to recall the file from tape without triggering

recall</span>

<br><span style=" font-size:10pt;font-family:Helvetica">storms.</span>

<br><span style=" font-size:10pt;font-family:Helvetica">Use the following

</span><span style=" font-size:10pt;font-family:Helvetica-Bold"><b>dsmmigfs

</b></span><span style=" font-size:10pt;font-family:Helvetica">command

options to set both the stub size and preview size of</span>

<br><span style=" font-size:10pt;font-family:Helvetica">the file system

being managed by IBM Spectrum Archive EE:</span>

<br><span style=" font-size:10pt;font-family:BookMasterGothic-Bold"><b>dsmmigfs

Update -STUBsize</b></span>

<br><span style=" font-size:10pt;font-family:BookMasterGothic-Bold"><b>dsmmigfs

Update -PREViewsize</b></span>

<br><span style=" font-size:10pt;font-family:Helvetica">The value for the

</span><span style=" font-size:10pt;font-family:BookMasterGothic-Bold"><b>STUBsize

</b></span><span style=" font-size:10pt;font-family:Helvetica">is a multiple

of the IBM Spectrum Scale file system’s block size.</span>

<br><span style=" font-size:10pt;font-family:Helvetica">this value can

be obtained by running the </span><span style=" font-size:10pt;font-family:BookMasterGothic-Bold"><b>mmlsfs

<filesystem><span style=" font-size:10pt;font-family:Helvetica">.

The </span><span style=" font-size:10pt;font-family:BookMasterGothic-Bold"><b>PREViewsize

</b></span><span style=" font-size:10pt;font-family:Helvetica">parameter</span>

<br><span style=" font-size:10pt;font-family:Helvetica">must be equal to

or less than the </span><span style=" font-size:10pt;font-family:BookMasterGothic-Bold"><b>STUBsize

</b></span><span style=" font-size:10pt;font-family:Helvetica">value. Both

parameters take a positive integer in</span>

<br><span style=" font-size:10pt;font-family:Helvetica">bytes.</span><span style=" font-size:10pt;font-family:sans-serif"><br>

</span>

<br>

<p style="■;margin-Bottom:240px"><span style=" font-size:9pt;font-family:Arial"> </span></p>

<br><span style=" font-size:10pt;font-family:Arial">Regards,</span>

<br><span style=" font-size:10pt;font-family:Arial"> </span>

<br><span style=" font-size:14pt;color:#8f8f8f;font-family:Arial"><b>Indulis

Bernsteins</b></span><span style=" font-size:10pt;font-family:Arial"><br>

Systems Architect<br>

IBM New Generation Storage</span>

<br>

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+44 792 008 6548</span><span style=" font-size:10pt;color:#4181c0;font-family:Arial"><b><br>

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<u>INDULISB@UK.IBM.COM</u></span>

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