IBM’s New Midrange with Easy Tier & External Virtualization

Yes, IBM has announced a new midrange virtualized disk system, the Storwize V7000. A veritable CLARiiON-killer : )

The announce detail should be well covered elsewhere (on www.ibm.com/storage and by Barry Whyte & Tony Pearson for example, if not yet then very shortly) so what you get here is mainly my view on the two major value points of Storwize V7000:

1. Virtualization of external disk systems
2. Easy Tier (automated sub-lun data relocation)

I have previously blogged about Easy Tier on the DS8000. It’s great to see IBM cross-pollinating the product set with features – it looks like someone in development has done a great job of getting the various development teams together to share code. What we see with both Storwize V7000 and SVC 6.1 are products built from a code base of SVC 5.1, with a user interface inherited from XIV, and Easy Tier and a robust RAID implementation inherited from DS8000. EMC’s Mark Zilla Twomey has in the past referred to IBM’s separate ivory towers of product development, well Storwize V7000 and SVC6.1 demonstrate that there is actually a very collegial approach taken to product development within IBM and there are no ivory towers.

Key components of Storwize V7000 are:

• Green shades denote SVC 5.1 software that forms a common base for both SVC 6.1 and Storwize V7000.
• Blue denotes existing software from the DS8000 DA adapter that has been included in both SVC 6.1 and Storwize V7000
• Pink denotes new components in SVC 6.1 and Storwize V7000 (management of hardware enclosure and PSU applies to Storwize V7000 only).
• Note that because they use the same software stack, Storwize V7000 has essentially the same interop list as SVC

The external virtualization story is very tidy i.e. you can effectively use your Storwize V7000 disk system as an SVC. This pretty much covers the simpler, more cost-effective virtualization for smaller customers that I called for in my blog post “One size does not fit all“.

The other big feature of Storwize V7000 is Easy Tier. Easy Tier is about extracting value from SSDs. Some folks think that SSDs are going to replace all other storage in the next few years, but the science doesn’t support that, and looking out 5 years it’s clear that spinning disks will continue to provide the bulk of enterprise disk capacity, with SATA (or more likely it’s SAS-fronted sibling, often referred to as ‘Nearline SAS’) leading the charge in reducing cost per TB.

So the challenge is how to extract maximum value from these expensive little puppies we call SSDs, plus take advantage of the lower cost per TB of large SAS and NL-SAS/SATA drives without compromising performance.

Automatic tiering that is easy and cost-effective for the midrange is the killer app that Storwize V7000 delivers on. There’s not much value in a tiering system that is complex or requires multiple elements of charegable add-on software. IBM’s Easy Tier will tune your system, automagically migrating 256MiB extents to and from SSD as required (from SAS or Nearline SAS/SATA) giving preference to small random reads (the workload most suited to SSDs).

Let me summarise from the Easy Tier Redpiece:

I/O operation	Typical SSD relative to HDD
Random Read	100 times faster
Random Write	40 times faster
Sequential Read or Write	2 times faster

Easy Tier will only move random I/Os to SSD. For every extent, Easy Tier will look at the following:

• I/O size, and whether it is a read or a write and random or sequential
• I/O rate and latency

Easy Tier will calculate the ‘temperature’ of each extent and will migrate the hot extents from the HDD to the SSD, based on highest temperature first.

The extent relocation algorithms factor in the cost of moving an extent into the decision to relocate. Volumes can also be excluded from Easy Tier, so that several apps may be served from a storage pool and only your performance critical ones tagged to reap the gains from SSDs/Easy Tier.

Storwize V7000 has inherited thin provisioning from it’s SVC code-base, and thin provisioning on this architecture provides excellent performance and is fully supported in an Easy Tier environment – something some other vendors might struggle with.

Also, if you don’t have any SSDs, you can still turn Easy Tier on and it will give you some conservative estimates on what improvements it could make to your performance if you did add SSDs.

Storwize V7000’s Easy Tier function is smart, easy and free (of course you probably want to buy at least three SSDs).

I hope that Easy Tier and Storwize V7000 will become synonymous in the midrange. Other vendors may hold their SSD value-extraction systems back by charging large for them, or by making them complicated, or using them as relatively basic caches, but IBM has made it easy and affordable and smart, and I love it when someone makes smarter technology affordable so that it can be widely adopted.

Also worth noting is that the following features are included in the base Storwize V7000 product, with no additional licences required:

1. Easy Tier
2. High performance thin provisioning for tier1 apps with no performance caveats
3. Local volume mirroring (e.g. between internal disk and an externally virtualised disk system)
4. Flashcopy (snapshot+writable snaps+clones+instant restore of snapped volumes)

This I like, because it unlocks innovation – the features get deployed in real life rather than staying on the brochure as happens with some other vendors midrange disk systems.

Storwize V7000 delivers fantastic performance, function and ease of use, bringing to an end the easy run our competitors have had in the midrange space up to now. With EMC delaying CX5 until 2011, and EVA on the back foot after the Left Hand and 3PAR acquisitions, Storwize V7000 will be hard to beat.