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1 PrernaAwasthi commented Permalink

Hi <br /> Are there any generic sizing guidelines for RAMSAN storage , As we know that RAMSAN can support more then 3lakh I/Ops . Is there any specific parameter which we need to tune with NPIV settings , are there any spcifc processor requirement, <div>&nbsp;</div> I went through some of the available documents , however i couldn't get any sizing specific guidelines with RAMSAN storage,

2 nagger commented Permalink

Hello, not sure why an IBMer is asking this question via a public blog comment! I don't have specific information but the release notes that come with the product might have recommended settings. Obviously a large Queue Depth is needed. As for CPU requirements that is a rather upside down question. It will be the same CPU cycle requirements as for hard disks (you will still be running a device driver to the adapter) - its just that the disks will respond much more quickly. I seriously doubt that most application could demand all the IOPS available - the application has to create or manipulate the data and that takes CPU time. The point is that the time wasted waiting for the disks to response becomes nearly zero so your application runs faster i.e. zero disk bottlenecks. This could drive up your CPU use but only because the applications no longer waits. Best of luck, Nigel

3 Mike_Pete commented Permalink

I've been using ndisk (ndisk64_75 actually) to do some comparisons between regular SAN backed vscsi and SSP (VIO but I have hit some sort of a problem. ndisk will run just fine several times but then will just stop working. Once broken, I can't get it to work again without rebooting. I've tried using different options (read vs write and others), changing files, logging back in, and changing users but nothing seems to clear this error. Anyone have any ideas? The error is below, hopefully it pastes correctly. <div>&nbsp;</div> ERROR: File exists <br /> Assert failure: SYSCALL retured -1:errno=17 <br /> File=ndisk64.c, Function=main, Line=1430, <br /> Operation="shmid_parallel = shmget(shm_user_key, shm_size, 0020000 | 0000400 | 0000200 | 0002000)" <br /> Memory fault(coredump)

4 nagger commented Permalink

You might have Control-D the run and left IPC resource as ndisk64 did not complete and tidy up. <br /> Run: ipcs -m <br /> Look for entries with a a KEY of 0xdeadbeef or 0xbeefdead. Then use ipcrm to remove them but only them!! <br /> Thanks Nigel Griffiths