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1 localhost commented Permalink

Thanks for another good informative post.<div>&nbsp;</div> Quick question:"If you copy A-&gt;B-&gt;C, virtual disks 'A' and 'B' are sources and so count towards the FlashCopy entitlement ('B' and 'C' are targets)."<div>&nbsp;</div> So...I think I understand, but just want to double check on what licenses are required when using a SEV flashcopy as a source of another.<div>&nbsp;</div> Assuming that B is a SEV Flashcopy of A, do you need a license the 'full' size of A + full size of B, or just the full size of A + the current SEV physical size of B?<div>&nbsp;</div> <div>&nbsp;</div> <div>&nbsp;</div>

2 localhost commented Permalink

Han,<div>&nbsp;</div> Thanks, glad you've found this little series of posts useful.<div>&nbsp;</div> As for your question, FlashCopy is licensed by the VIRTUAL capacity in source disks. So the virtual capacity of B in this case is the same as the virtual size of A. So is virtual size of A + virtual size of B. (not real size of B)<div>&nbsp;</div> It would be a nightmare for you to manage the license usage if it were based on the real size, as its likely to be constantly changing if you are using SEFC.<div>&nbsp;</div> Barry

3 localhost commented Permalink

Barry,<div>&nbsp;</div> Congratulations for this blog !Very usefull and TOP information !<div>&nbsp;</div> You said: "Virtual Disk Mirroring is not a disaster recovery solution due to both copies being accessed by the same node pair and only addressable by a single cluster in one site."<div>&nbsp;</div> But, what about a dispersed cluster ?Can I have the mirrored vDisk using one disk by a pair and another disk in the other pair accessed by a dispersed cluster of servers too ?Can I use this for Oracle RAC ou VMware VMFS to achieve a "application-cluster" in dispersed sites ?<div>&nbsp;</div> Regards,Claiton

4 localhost commented Permalink

Claiton,<div>&nbsp;</div> Thanks, glad you find my blog useful. <div>&nbsp;</div> So VDM is all about local HA. As far as the host or operating system is concerned it only sees one disk (the vdisk) which happens to be mirrored. So this is mirrored behind SVC not infront.<div>&nbsp;</div> So I don't think you can use it in the way you are proposing.<div>&nbsp;</div> Barry<div>&nbsp;</div>

5 localhost commented Permalink

Hi Barry,<div>&nbsp;</div> I have a quick question about the IBM SVC.<div>&nbsp;</div> I was wondering when SVC will support greater than 2TB vdisk/mdisk?<div>&nbsp;</div> Thank-you and best regards,<div>&nbsp;</div> Evan

6 localhost commented Permalink

Hi Barry,<div>&nbsp;</div> some SVC customers installed their SVC Nodes in a split cluster configuration with a quorum disk in a third location. Distances in that cases are usually below 500 meters.<div>&nbsp;</div> For that kind of installations - will they have now, with SVC 4.3 and VDM, a disaster recovery storage solution ?<div>&nbsp;</div> Do you see some drawbacks of the above solution compared to a metro mirror solution, except the fact, that the svc cluster itself is a single point of failure ?<div>&nbsp;</div> Thanks a lot - You've done a good job the last years.<div>&nbsp;</div> Andreas<div>&nbsp;</div> <div>&nbsp;</div> <div>&nbsp;</div> <div>&nbsp;</div> <div>&nbsp;</div>

7 localhost commented Permalink

Hi Andreas,<div>&nbsp;</div> As with the split-cluster configurations we need to validate each proposal via the RPQ process.<div>&nbsp;</div> If you (or a customer) is interested in validating a proposal for support of such a solution you will need to submit an RPQ so it can be validated. There would be caveats and the details can be discussed for each proposed solution.<div>&nbsp;</div> I personally can't think of any major drawbacks, other than the need to run dedicated fibre connections between the core SVC switches and the storage at each site, since we don't support ISLs between SVC and storage. Although thats just off the top of my head, there maybe some hidden gotchas I haven't though of yet.<div>&nbsp;</div> The RPQ team will be able to help in that respect too.