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It is best to leave the MDT recordsize at the default. For most files it will not matter (too small), but for Data on MDT you also don't want a large recordsize. <br>
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<div id="AppleMailSignature">Cheers, Andreas</div>
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On Sep 28, 2018, at 09:17, Robert Redl <<a href="mailto:robert.redl@lmu.de">robert.redl@lmu.de</a>> wrote:<br>
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<p>Dear All,</p>
<p>I have a related question. The documentation says nothing about the recommended recordsize for MDTs with ZFS backend. Are there any recommendation? Or is data on MDTs stored in a way that the recordsize does not matter?</p>
<p>Thanks,<br>
Robert<br>
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<div class="moz-cite-prefix">On 09/28/2018 12:54 AM, Andreas Dilger wrote:<br>
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Firstly, we don't test anything larger than 1MB.
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<div>Secondly, the best recordsize is up to the apication IO pattern. If it is streaming writes, it might be OK. If it is random write then probably not. <br>
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<div id="AppleMailSignature">Cheers, Andreas</div>
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On Sep 27, 2018, at 19:04, Riccardo Veraldi <<a href="mailto:Riccardo.Veraldi@cnaf.infn.it" moz-do-not-send="true">Riccardo.Veraldi@cnaf.infn.it</a>> wrote:<br>
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<p>Hello,</p>
<p>I have always been using ZFS record size to 1MB with Lustre on top of ZFS. Anyway it is possible to set it to more than 1MB. May this have any benefit in performance and is it recommended to set for example:</p>
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<pre>echo 4194304 > /sys/module/zfs/parameters/zfs_max_recordsize</pre>
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<pre>zfs set recordsize=4m zpool
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<p>Thank you.</p>
<p>Rick</p>
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