June Q&A

When looking at the blog stats for reader numbers (never more than 5 times a day) one area that often catches my eye is the “search terms used to find your blog” column.  Many times I get the feeling that whoever has clicked on this blog after typing a particular search term, probably hasn’t got the answer they were looking for.  So in the interests of fairness (and since it’s friday), I thought I’d answer a few of the more common ones:

Q: Gorilla Box Storage

A: Sorry, this isn’t me

Q: Gorilla Case Storage

A: Still isn’t me (sorry)

Q: Gorilla Glue

A: Nosir, none of that here

Q:  Variations on the Theme “IBM XIV Problems”:

A:  Yup, XIV has problems.  Whether you think they are insurmountable will very much depend on your need for the product (if you’re a small business committed to running AIX 5.2 and wanting iSCSI for less than 20TB, then I suggest looking elsewhere).  Personally I don’t feel that any one item is a killer, and even the sum of the parts is still infinitely less than the crap I have to put up with from other vendors – the trade-off in ease of use and performance is worth it for a bunch of minor niggles.

Q:  NetApp or Lefthand?

A:  Depends what you’re looking for.  If you need small to medium scale iSCSI for applications, databases and other block requirements (VMware), and don’t mind proliferation of small storage arrays (or maybe have a number of distributed sites) go for HP Lefthand or Dell Equalogic.  If you’re looking for market-leading file server environments (of the same approximate size), look more at NetApp’s 2000 range.  I have a real issue with running applications on a file system, so don’t have much time for NetApp as a database or VM platform.

Q:  AIX not seeing IBM XIV FC LUNs

A:  Have you tried:

  • Turning it off, then on (sorry, couldn’t resist the AOL solution 🙂 )
  • Installing all relevant hotfixes
  • Installing the host attachment kit from the IBM website (Solaris shows up fine in the XIV without the HAK installed, AIX tends to sulk until it has its MPIO)
  • Attaching to XIV via a SAN (the only OS that insists on SAN attachment, AIX has dragged all others down with it)

Q:  Variations on “XIV or Clariion?”

A:  Had an interesting discussion over email on this a week or so ago (reposted in the comments section of my original article by kind permission of the sender).

Overall my feeling is that both are good technologies in the market as it stands.  Over time, I think the Clariion-type architecture will be superseded by variations on the Parallel Grid used by XIV, but right now, both serve a purpose.  In the sub-20TB range, Clariion would probably be more economical, but for >20TB, >20,000 IOPS it becomes a matter of pricing and discounting, particularly once EMC get unisphere into the public domain.  >40,000 IOPS I don’t see a contest – I’d put in an XIV anytime (unless you have V-Max money to spend, in which case it would be 4 XIV’s 🙂 ).

Q:  XIV or EVA?

A:  To the two people who asked this – XIV

(or just about any other array on the market, really.  Sorry HP, I love your servers and buy your printers, but isn’t it time you took these abominations out back of the barn and shot them in the head?)

Q:  XIV Async Minimum

A:  Minimum what?

Q:  Does XIV support RAID 6?

A:  Not yet, and if/when it comes, it probably won’t resemble the RAID 6 implemented elsewhere.  Just as the current layout isn’t restricted to using a specific set of disks (and so isn’t actually RAID at all in the strictest sense) protecting against triple failures on an XIV would involve a sort of 1+1+1 set of three copies spread across all disks.  Given the impact on capacity, this would probably have to be limited to 2TB disk models and above, as a 1TB model would end up with only 40TB usable .

Q:  IBM XIV worth a look?

A:  If not evident by now, I think so.  Whatever the use, it’s worth at least an evaluation, even if the eventual answer is no.


A:  Not yet, maybe not ever if IBM keep it up

Hope this helps – if I’ve missed anything, please let me know at the usual address.



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