<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Thanks Luke,<div class=""><br class=""></div><div class="">The whole business of “promoting” a cache from one type to another isn’t documented very well in the places that I am looking. I would be grateful to anyone with more info to share.</div><div class=""><br class=""></div><div class="">I am in the process of investigating Async DR for new customers. It would just be useful to see what can be done with existing ones who have no interest in upgrading.</div><div class=""><br class=""></div><div class="">Also Async DR means that I have to create snapshots (and worse delete them) on the “working” side of a replication pair and this is something I’m not in a tearing hurry to do.</div><div class=""><br class=""></div><div class=""> </div><div class="">Regards,</div><div class=""><br class=""></div><div class="">Vic</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 19 Apr 2016, at 11:46, Luke Raimbach <<a href="mailto:Luke.Raimbach@crick.ac.uk" class="">Luke.Raimbach@crick.ac.uk</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Hi Shankar, Vic,<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Would it not be possible, once the original cache site is useable, to bring it up in local-update mode so that you can pre-fetch all the metadata from home?<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Once you are ready to do the switchover: stop writing to home, do a final sync of metadata, then “promote” the local-update cache to a single-writer; continue writing new data in to the original cache.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">I am assuming the only reason you’d want to repopulate the SW cache with metadata is to prevent someone accidentally creating the same file after the disaster and overwriting the original at home without any knowledge?<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Cheers,<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Luke.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><a name="_MailEndCompose" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""><o:p class=""> </o:p></span></a></div><div style="border-style: none none none solid; border-left-color: blue; border-left-width: 1.5pt; padding: 0cm 0cm 0cm 4pt;" class=""><div class=""><div style="border-style: solid none none; border-top-color: rgb(225, 225, 225); border-top-width: 1pt; padding: 3pt 0cm 0cm;" class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><b class=""><span lang="EN-US" style="font-size: 11pt; font-family: Calibri, sans-serif;" class="">From:</span></b><span lang="EN-US" style="font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span class="Apple-converted-space"> </span><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" style="color: purple; text-decoration: underline;" class="">gpfsug-discuss-bounces@spectrumscale.org</a><span class="Apple-converted-space"> </span>[<a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" style="color: purple; text-decoration: underline;" class="">mailto:gpfsug-discuss-bounces@spectrumscale.org</a>]<span class="Apple-converted-space"> </span><b class="">On Behalf Of<span class="Apple-converted-space"> </span></b>Shankar Balasubramanian<br class=""><b class="">Sent:</b><span class="Apple-converted-space"> </span>19 April 2016 06:47<br class=""><b class="">To:</b><span class="Apple-converted-space"> </span>gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org" style="color: purple; text-decoration: underline;" class="">gpfsug-discuss@spectrumscale.org</a>><br class=""><b class="">Subject:</b><span class="Apple-converted-space"> </span>Re: [gpfsug-discuss] AFM Question<o:p class=""></o:p></span></div></div></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class="">SW mode does not support failover. IW does, so this will not work.<span class="Apple-converted-space"> </span></span><br class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class=""><br class=""><br class="">Best Regards,<br class="">Shankar Balasubramanian<br class="">AFM & Async DR Development<br class="">IBM Systems<br class="">Bangalore - Embassy Golf Links<span class="Apple-converted-space"> </span><br class="">India<br class=""><br class=""></span><br class=""><br class=""><br class=""><br class=""><span style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(95, 95, 95);" class="">From: </span><span style="font-size: 7.5pt; font-family: Arial, sans-serif;" class="">Vic Cornell <<a href="mailto:viccornell@gmail.com" style="color: purple; text-decoration: underline;" class="">viccornell@gmail.com</a>></span><br class=""><span style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(95, 95, 95);" class="">To: </span><span style="font-size: 7.5pt; font-family: Arial, sans-serif;" class="">gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org" style="color: purple; text-decoration: underline;" class="">gpfsug-discuss@spectrumscale.org</a>></span><br class=""><span style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(95, 95, 95);" class="">Date: </span><span style="font-size: 7.5pt; font-family: Arial, sans-serif;" class="">04/18/2016 07:13 PM</span><br class=""><span style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(95, 95, 95);" class="">Subject: </span><span style="font-size: 7.5pt; font-family: Arial, sans-serif;" class="">[gpfsug-discuss] AFM Question</span><br class=""><span style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(95, 95, 95);" class="">Sent by: </span><span style="font-size: 7.5pt; font-family: Arial, sans-serif;" class=""><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" style="color: purple; text-decoration: underline;" class="">gpfsug-discuss-bounces@spectrumscale.org</a></span><o:p class=""></o:p></div><div class="MsoNormal" align="center" style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; text-align: center;"><hr size="3" width="100%" noshade="" align="center" style="color: rgb(160, 160, 160);" class=""></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><br class=""><br class=""><br class="">Hi All,<o:p class=""></o:p></div><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Is there a bandwidth efficient way (downtime is allowed) to reverse the relationship between HOME and CACHE in a single writer AFM relationship?<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">If it is not immediately obvious why this might be useful, see the following scenario:<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Fileset A is a GPFS fileset which is acting as CACHE for a single writer HOME on fileset B located on a separate filesystem.<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">The system hosting A fails and all data on fileset A is lost.<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Admin uses fileset B as a recovery volume and users read and write data to B until the system hosting A is recovered, albeit without data.<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Admin uses mmafmctl to “failover” AFM relationship to a new fileset on A, all data are copied from B to A over time and users continue to access the data via B.<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">So is there a bandwidth efficient way (downtime is allowed) to reverse the relationship between A and B such that the replication flow is as it was to start with?<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Cheers,<o:p class=""></o:p></p><p style="margin-right: 0cm; margin-left: 0cm; font-size: 12pt; font-family: 'Times New Roman', serif; margin-bottom: 12pt;" class="">Vic<br class=""><tt style="font-family: 'Courier New';" class=""><span style="font-size: 10pt;" class="">_______________________________________________</span></tt><span style="font-size: 10pt; font-family: 'Courier New';" class=""><br class=""><tt style="font-family: 'Courier New';" class="">gpfsug-discuss mailing list</tt><br class=""><tt style="font-family: 'Courier New';" class="">gpfsug-discuss at<span class="Apple-converted-space"> </span><a href="http://spectrumscale.org/" style="color: purple; text-decoration: underline;" class="">spectrumscale.org</a></tt><br class=""></span><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" style="color: purple; text-decoration: underline;" class=""><tt style="font-family: 'Courier New';" class=""><span style="font-size: 10pt;" class="">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</span></tt></a><span style="font-size: 10pt; 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