• My writing
  • First up, a battery charger? La Crosse BC-700 Review: A Battery Charger That Does Not Suck
  • I urge you to See W. Curtis Preston’s Backup Central Live!
  • I was looking for The Best Network Card For VMware ESX Home Lab Machines
  • From my Network Computing blog: Unified Storage: What Is It Good For?
  • I was amazed to see the result of my HP Photosmart printer series: The Power of Negative Publicity
• Other great links
  • Chris Evans wrote a solid piece for Datamation: Virtualization and Storage: Overview, Vendor Solutions
  • Matt Simmons talks about dealing with storage: I’m here to shard data and chew bubblegum…
  • Alex Popescu’s 5 Approaches to Scalable Storage Solutions led to Jeff Darcy’s Introduction to Distributed Filesystems
  • Xangati talks Field Day: Running Comprehensive and Deep at Tech Field Day #5
  • And then there’s Wireless Field Day, courtesy of Andrew von Nagy: Shamrockin’ the Wireless Industry
  • Greg Ferro continues spreading the word on FCoTR: Presenting Silvano Gai With FCoTR Button
  • Howard Marks takes up the topic of specialized hard disk drives: Yes, Virginia, RAID Drives Are Different
  • Howard was spurred by Simon Gallagher, among others: Home Labbers beware of using Western Digital SATA HDDs with a RAID Controller
  • The continuing saga of Google Chrome and H.264 takes a weird turn: Microsoft adds H.264 support to Google Chrome
  • Simon Long fights the good fight, presenting solid technical info: VMware View Desktops: IDE or SCSI? BusLogic, LSI Logic or PVSCSI?
  • A key topic in storage is the balance between performance and capacity, as noted by Xiotech: Performance and Capacity Tradeoffs and the Rise of a New Class of Storage
  • An amusing infographic: The United States of Shame (CHART)
  • Kevin Houston takes on Cisco UCS: What Cisco Has to Do to Win the Blade Server Market
  • Finally, Jeremy Gaddis is back with Bypassing the Internet Kill Switch

Subscribe to my Google Reader feed or follow me on Twitter to see these in real-time.

© sfoskett for Stephen Foskett, Pack Rat, 2011. | Back From the Pile: Interesting Links, February 4, 2011
This post was categorized as Enterprise storage, Personal, Terabyte home, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

For more information on earlier updates, see my articles:

• Storage Fixes in VMware ESX Server 3.5 Update 2
• Storage Changes in VMware ESX 3.5 Update 3
• Storage Changes in VMware ESX 3.5 Update 4
  

One first step is VMware’s whitepaper, “What’s New in VMware vSphere 4: Storage“.

Licensing and Availability of Features

The most important change at a glance is in the licensing model for VMware.

• A new low-end “standard” level includes all of the components a small business might need, including thin provisioning of storage, at a very attractive price.
• The “advanced” level includes advances in the area of data protection.
• At the “enterprise” level, live migration of storage is enabled.
• Top of the heap is “enterprise plus”, which enables the intriguing plug-in third-party multipathing support previously rumored.
• Enterprise customers with current support will get vStorage thin provisioning and data protection when they upgrade.

Each step up the licensing ladder enables important new storage features (source: VMware)

Thin Provisioning

One of the most widespread storage features is native thin provisioning. VMware ESX 4 will allocate storage in 1 MB chunks as capacity is used. This isn’t really completely new – similar support was enabled by default for virtual disks on NFS in VI 3, and thin provisioning could be enabled on the command line for block-based storage as well. It was also present in VMware’s desktop products, including my own copy of Fusion. And ESX allows thick-to-thin conversion during Storage VMotion.

The difference with vSphere 4 is that thin provisioning is fully supported and integrated into every version of ESX. Although many storage arrays now also offer thin storage, the addition of native, integrated thin provisioning right in ESX is huge. This alone will be a major capacity (and thus, cost) savings feature! VMware claims 50% storage savings in their lab tests.

Dynamic Expansion of VMFS Volumes

VMFS volumes can now grow (and, in some cases, shrink) online without resorting to spanning to a new LUN. Under vSphere 4, VMFS volumes can grow to take advantage of expanded LUNs (up to 2 TB per LUN). The old method still works as well, and multi-LUN spanned VMFS volumes can grow when any of their LUNs is expanded.

Enhanced Storage VMotion

Like thin provisioning, Storage VMotion has been elevated to first-class status, supported just about everywhere you’d want it. It’s in all the likely spots within vCenter.

Storage VMotion gives serious storage flexibility now, enabling (almost) any-to-any migration of VMFS volumes: Pick up a Fibre Channel, iSCSI, or NFS disk image and move it to another datastore running any of those protocols to convert live. And you can do thick-to-thin provisioning at the same time.

Under the hood, the whole infrastructure has been revised. Storage VMotion leverages VMware’s change block tracking instead of disk snapshots now, speeding up the migration process and reducing the (formerly excessive) memory and CPU requirements of Storage VMotion in 3.5. This is the same technology leveraged by vSphere’s High Availability features, by the way.

Pluggable Storage Architecture (PSA)

Only “Enterprise Plus” licensees will get to use it, but the vSphere family also sports a new pluggable storage architecture (PSA) which will initially be leveraged to deliver vendor-specific multipath support. Note that the native multipath support in vSphere continues to be a basic round-robin or fail-over system – it will not dynamically load balance I/O across multiple paths or make more intelligent decisions about which paths to use.

vSphere 4's Pluggable Storage Architecture allows third-party developers to replace ESX's storage I/O stack (source: VMware)

As you may gather from this VMware illustration (but would probably miss since it’s not all that comprehensible), there are two classes of third-party plug-ins:

1. Basic path-selection plugins (PSPs) will merely optimize the choice of which path to use, ideal for active/passive type arrays
2. Full storage array type plugins (SATPs) will allow load balancing across multiple paths in addition to path selection for active/active arrays

EMC also announced PowerPath/VE for vSphere, integrating their popular multi-platform path management software directly into ESX. It’s not clear at this point whether PowerPath will require an Enterprise Plus license (or if it will come with one) or if it will work with all editions, but I’m sure that will be clarified soon. My EMC contacts do tell me that PowerPath/VE is licensed on a per-socket basis (like VMware of yore) and that EMC sales reps have some room to get creative on licensing.

iSCSI Software Initiator Enhancements

It’s harder to claim it as a new feature, but the iSCSI software initiator has also been tweaked and tuned to use less CPU time and deliver better throughput. The iSCSI configuration process has also been smoothed out so one no longer needs to have a live Service Console connection in order to communicate with an iSCSI target. And changes made in the general tab are now global, so they’ll propagate down to each target. Bi-directional CHAP is also added, so the target can now be authenticated in addition to the initiator.

vSphere also includes a paravirtualized iSCSI driver (PVSCSI) which works like vmxnet to present a higher-performance iSCSI adapter within certain supported guest OSes.

More information on multipathing iSCSI can be found at Yellow Bricks and in Chad Sakac’s mega-post on the topic.

High-Performance I/O

vSphere really pours on the I/O power. They claim a 3x increase, to “over 300,000 I/O operations per second”, but mentioned in the launch that they’ve gotten to 400,000 in some workloads. This is really amazing, and if it’s true in real-world use means that VMware ESX can now host just about any application you can think of.

It’s funny, but just a few weeks before the announcement VMware’s Chief Data Center architect, Scott Davis, told me at Storage Networking World that vSphere would double I/O performance. I thought this was a bold statement at the time, but VMware went further in their official documents, claiming 3x improvement. Now we have an on-stage admission that it could be up to 4x! This is serious stuff, folks: Can VMware really do 400,000 IOPS?

One question is whether these IOPS improvements require the new VMDirectPath I/O for Storage, which binds a physical Fibre Channel HBA to a single guest OS, or if they’re generalized across all systems.

vCenter Improvements

vCenter now includes more storage information:

• Each VM and ESX in the inventory has a tab showing storage information and allowing users to set alarms on storage use – setting capacity alarms becomes extremely important when thin provisioning is used!
• vCenter inventory has a view showing datastore details
• There’s also a nice storage topology map

Data Protection APIs (Updated)

VMware also enhanced the APIs for consolidated backup (VCB) into “vStorage Data Protection”. Available only with Advanced or Enterprise licenses, these APIs allow enterprise backup vendors to develop specific integration with VMware without VCB in the middle.  All versions of ESX include this vStorage API and boast VCB support. Standard and Essentials licenses do not include vCenter Data Recovery, a standalone disk-to-disk backup capability for virtual machines.

Conclusion

vSphere is loaded with storage improvements, though many seem like incremental updates rather than new features. Admins will welcome thin provisioning support, and the full integration of Storage VMotion is certainly welcome, but I think the changes to vCenter will be most noticeable. I’ll be looking into EMC’s PowerPath/VE and the amazing I/O improvements as we move forward and learn more about the next ESX!

Duncan Epping posted much more vSphere Linkage on his Yellow Bricks blog if you’re interested in non-storage features. I also suggest reading Chris Evans’ outline of vSphere storage changes.

© sfoskett for Stephen Foskett, Pack Rat, 2009. | Storage Changes in the VMware vSphere 4 Family
This post was categorized as Enterprise storage, Gestalt IT, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

PVSCSI gives virtual machines direct access to SCSI and FC HBAs, and plays nicely with NPIV (Xensummit diagram by Fujitsu)

Functionally similar to VMware’s Physical Compatibility Mode for Raw Device Mode (RDM) volumes, PVSCSI enables certain applications that require direct SCSI communication to function in a virtual environment. Examples include Oracle RMAN, backup applications, and potentially SAN management software.

PVSCSI plays nicely with N_Port ID Virtualization (NPIV), too, so you don’t need to assign a physical HBA port to each guest – they can all share a port or two, and each would have his own N_Port on the Fibre Channel fabric.

In their Xensummit presentation about PVSCSI, Fujitsu showed impressive performance numbers, demonstrating that the technology doesn’t cause much of a performance hit even though it is substantially more complicated than the alternative approaches. I do wonder how PVSCSI managed to outperform Dom0 with 128k writes, but let’s chalk that up to insignificant variations in timing…

Now if only Xen would update the (3.2-era) readme files on their download page!

© sfoskett for Stephen Foskett, Pack Rat, 2008. | Xen 3.3 Update Brings Paravirtualized SCSI
This post was categorized as Enterprise storage, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.