Comments on: Enterprise Computing: The Wide Striping Debate

By: zsr

zsr — Sat, 03 Apr 2010 17:28:22 +0000

[...] … Thursday, 09 03th, 2009 at 11:06 AM. Category : Uncategorized. Do More : You can leave a …The Storage Architect Blog Archive Enterprise Computing …Storage and Virtualisation … Are you suggesting that VP ZSR will be less efficient on V-Max than [...]

By: VIRTUMANIA Episode 5: Sir Mix-A-Lot Storage Virtualization | VM /ETC

VIRTUMANIA Episode 5: Sir Mix-A-Lot Storage Virtualization | VM /ETC — Wed, 31 Mar 2010 02:57:00 +0000

[...] Enterprise Computing: The Wide Striping Debate [...]

By: Nigel

Nigel — Wed, 15 Jul 2009 14:59:04 +0000

So Barry,

In saying “..And indeed, if/when V-Max VP supports zero space reclaim, it will inherently be more efficient than Hitachi DP thanks to the smaller chunk/page/extent size of VP (768KB vs. 42MB)…” Are you suggesting that VP ZSR will be less efficient on V-Max than on 3PAR as 3PAR has an even smaller chunk/page/extent? Not as simple as that otherwise we’d probably all have 1K extents (OK obviously not but its not all that simple is it).

And interesting that none of those extolling the virtues of 3PAR above have piped up with explanations of why what 3PAR does is better than what the likes of HDS and EMC do. Hmmmmmmmm! (or may be they dont follow the comments feed on here) No probs as Im pretty sure I already know anyway…….

By: Nigel

Nigel — Tue, 14 Jul 2009 13:12:43 +0000

Can any of the above who bring up 3PAR RAID at the 256MB chunklet level offer any more information on how this is better than traditional RAID Groups for lowering the risk of double disk failures?

My understanding, albeit limited, is that it lowers the “possibility”, but that the possibility exists….

Also the 3PARs dont currently offer the ability to create storage pools. Its all your eggs in one basket scenario with an albeit lower risk of double disk failure. However, other technologies offer the ability to create multiple pools and spread your eggs among multiple baskets.

Im well aware of the limitations in the HDS implementation but am not so sure that its all that worse than the 3PAR implementation.

Thoughts??

By: the storage anarchist

the storage anarchist — Tue, 14 Jul 2009 11:01:15 +0000

Right now I can only say that reclamation of unused/all-zero space is just another common feature of thin provisioning. Likewise the ability to shrink a storage pool to remove/repurpose unused capacity (Hitachi DP doesn’t support this feature, V-Max VP does). Feature races are usually temporal – any feature advantage is generally short-lived.

And indeed, if/when V-Max VP supports zero space reclaim, it will inherently be more efficient than Hitachi DP thanks to the smaller chunk/page/extent size of VP (768KB vs. 42MB).

By: Chris Evans

Chris Evans — Tue, 14 Jul 2009 05:15:09 +0000

Martin/Jason

Thanks. As you say, “legacy” architecture. Unfortunately sometimes you can’t fit new technology into old hardware…

Chris

By: Chris Evans

Chris Evans — Tue, 14 Jul 2009 05:10:51 +0000

Barry

Thanks for that. Are you able to say whether/when EMC will have something like Zero Page Reclaim?

Chris

By: the storage anarchist

the storage anarchist — Tue, 14 Jul 2009 01:24:45 +0000

Clarification came out today that “Free VP” is available to all VP-supporing Symmetrix platforms, new or already installed. DMX3 & DMX4 must be running Enginuity 5773; all V-Max arrays support VP with Enginuity 5874.

By: Jason Jensen

Jason Jensen — Mon, 13 Jul 2009 20:27:15 +0000

You beat me to it Martin. My understanding of 3PAR RAID as well is that it is at the chunklet level and not the physical disk level.

By: Martin G

Martin G — Mon, 13 Jul 2009 14:59:37 +0000

The risk you state very much depends on how the wide-striping is implementing and how the RAID is implemented. I’m sure Marc will be along to correct me if I’m wrong but in 3PAR’s implementation, the RAID is at the chunklet level and not at the disk level. This has positive advantages in the rebuild times but also a double disk failure is unlikely to the impact you describe. At least, that was my understanding of 3Par’s implementation.

It is one of the advantages of starting without a legacy architecture…