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<p><font size="2" face="sans-serif">Hi Simon,</font><br>
<br>
<font size="2" face="sans-serif">HAWC leverages the System.log (or metadata pool if no special log pool is defined) pool.... so its independent of local or multi-cluster modes... small writes will be 'hardened' whereever those pools are defined for the file system.</font><br>
<font size="2" face="sans-serif"><br>
Dean Hildebrand<br>
IBM Master Inventor and Manager | Cloud Storage Software<br>
IBM Almaden Research Center<br>
</font><br>
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<img width="16" height="16" src="cid:1__=07BBF43DDF9265598f9e8a93df938@us.ibm.com" border="0" alt="Inactive hide details for "Simon Thompson (Research Computing - IT Services)" ---08/26/2015 05:58:12 AM---Oh and one other ques"><font size="2" color="#424282" face="sans-serif">"Simon Thompson (Research Computing - IT Services)" ---08/26/2015 05:58:12 AM---Oh and one other question about HAWC, does it work when running multi-cluster? I.e. Can clients in a</font><br>
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<font size="1" color="#5F5F5F" face="sans-serif">From: </font><font size="1" face="sans-serif">"Simon Thompson (Research Computing - IT Services)" <S.J.Thompson@bham.ac.uk></font><br>
<font size="1" color="#5F5F5F" face="sans-serif">To: </font><font size="1" face="sans-serif">gpfsug main discussion list <gpfsug-discuss@gpfsug.org></font><br>
<font size="1" color="#5F5F5F" face="sans-serif">Date: </font><font size="1" face="sans-serif">08/26/2015 05:58 AM</font><br>
<font size="1" color="#5F5F5F" face="sans-serif">Subject: </font><font size="1" face="sans-serif">Re: [gpfsug-discuss] Using HAWC (write cache)</font><br>
<font size="1" color="#5F5F5F" face="sans-serif">Sent by: </font><font size="1" face="sans-serif">gpfsug-discuss-bounces@gpfsug.org</font><br>
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<tt><font size="2">Oh and one other question about HAWC, does it work when running<br>
multi-cluster? I.e. Can clients in a remote cluster have HAWC devices?<br>
<br>
Simon<br>
<br>
On 26/08/2015 12:26, "Simon Thompson (Research Computing - IT Services)"<br>
<S.J.Thompson@bham.ac.uk> wrote:<br>
<br>
>Hi,<br>
><br>
>I was wondering if anyone knows how to configure HAWC which was added in<br>
>the 4.1.1 release (this is the hardened write cache)<br>
>(</font></tt><tt><font size="2"><a href="http://www-01.ibm.com/support/knowledgecenter/#!/STXKQY/411/com.ibm.spect">http://www-01.ibm.com/support/knowledgecenter/#!/STXKQY/411/com.ibm.spect</a></font></tt><tt><font size="2"><br>
>r<br>
>um.scale.v4r11.adv.doc/bl1adv_hawc_using.htm)<br>
><br>
>In particular I'm interested in running it on my client systems which have<br>
>SSDs fitted for LROC, I was planning to use a small amount of the LROC SSD<br>
>for HAWC on our hypervisors as it buffers small IO writes, which sounds<br>
>like what we want for running VMs which are doing small IO updates to the<br>
>VM disk images stored on GPFS.<br>
><br>
>The docs are a little lacking in detail of how you create NSD disks on<br>
>clients, I've tried using:<br>
>%nsd: device=sdb2<br>
> nsd=cl0901u17_hawc_sdb2<br>
> servers=cl0901u17<br>
> pool=system.log<br>
> failureGroup=90117<br>
><br>
>(and also with usage=metadataOnly as well), however mmcrsnd -F tells me<br>
>"mmcrnsd: Node cl0903u29.climb.cluster does not have a GPFS server license<br>
>designation"<br>
><br>
><br>
>Which is correct as its a client system, though HAWC is supposed to be<br>
>able to run on client systems. I know for LROC you have to set<br>
>usage=localCache, is there a new value for using HAWC?<br>
><br>
>I'm also a little unclear about failureGroups for this. The docs suggest<br>
>setting the HAWC to be replicated for client systems, so I guess that<br>
>means putting each client node into its own failure group?<br>
><br>
>Thanks<br>
><br>
>Simon<br>
><br>
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