Archive for August, 2011

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Quick-Take: VMworld 2011, Thoughts on the Airplane

August 28, 2011

On the way to VMworld this morning this morning I started-out by listening to @Scott_lowe, @mike_laverick and @duncanyp about stretched clusters and some esoteric storage considerations. Then i was off reading @sakacc blogging about his take on stretch clusters and the black hole of node failure when I stumbled on a retweet @bgracely via @andreliebovici about the spectre of change in our industry. Suddenly these things seemed very well related within the context of my destination: VMworld 2011.

Back about a month ago when vSphere 5 was announced the buzz about the “upgrade” was consumed by discussions about licensing and vRAM. Naturally, this was not the focus VMware was hoping for, especially considering how much of a step forward vSphere 5 is over VS4. Rather, VMware – by all deserved rights – wanted to hear “excited” conversations about how VS5 was closing the gap on vCloud architecture problems and pain-points.

Personally, I managed to keep the vRAM licensing issue out of SOLORI’s blog for two reasons: 1) the initial vRAM targets were so off that VMware had to make a change, and 2) significant avenues for the discussion were available elsewhere. That does not mean I wasn’t outspoken about my thoughts on vRAM – made obvious by contributions to some community discussions on the topic – or VMware’s reasoning for moving to vRAM. Suffice to say VMware did “the right thing” – as I had confidence they would – and the current vRAM targets capture 100% of my clients without additional licenses.

I hinted that VS5 answers a lot of the hanging questions from VS4 in terms of facilitating how cloud confederations are architected, but the question is: in the distraction, did VS5’s “goodness” get lost in the scuffle? If so, can they get back the mind share they may have lost to Chicken Little reactionaries?

First, if VMware’s lost ground to anyone, it’s VMware. The vast majority of cool-headed admins I talked to were either not affected by vRAM or were willing to take a wait-and-see outlook on vSphere 5 with continued use of vSphere 4.1. Some did evaluate Hyper-V’s “readiness” but most didn’t blink. By comparison, vSphere 4.1 still had more to offer private cloud than anything else.

Secondly, vSphere 5 “goodness” did get lost in the scuffle, and that’s okay! It may be somewhat counter intuitive but I believe VMware will actually come out well ahead of their “would be” position in the market, and it is precisely because of these things, not just in spite of them. Here’s my reasoning:

1) In the way the vSphere 5 launch announcement and vRAM licensing debacle unfolded, lot of the “hot air” about vRAM was vented along the way. Subsequently, VMware gained some service cred by actually listening to their client base and making a significant change to their platform pricing model. VMware got more bang-for-their-buck out of that move as the effect on stock price may never be known here, given the timing of the S&P ratings splash, but I would have expected to see a slight hit. Fortunately, 20-30% sector slides trump vRAM, and only Microsoft is talking about vRAM now (that is until they adopt something similar.)

On that topic, anytime you can get your competitor talking about your product instead of theirs, it usually turns out to be a good thing. Even in this case, where the topic has nothing to do with the needs of most businesses, negative marketing against vRAM will ultimately do more to establish VMware as an innovator than an “already too expensive alternative to XYZ.”

2) SOLORI’s law of conservation of marketing momentum: goodness preserved, not destroyed. VMworld 2011 turns out to be perfectly timed to generate excitement in all of the “goodness” that vSphere 5 has to offer. More importantly, it can now do so with increased vigor and without a lot of energy siphoned-off discussing vRAM, utilization models and what have you: been there done that, on to the meat and away with the garnish.

3) Again it’s odd timing, but the market slide has more folks looking at cloud than ever before. Confidence in cloud offerings has been a deterrent for private cloud users, partly because of the “no clear choices” scenario and partly because concerns about data migration in and around the public cloud. Instability and weak growth in the world economy have people reevaluating CAPEX-heavy initiatives as well as priorities. The bar for cloud offerings has never been lower.

In vSphere 5, VMware hints at the ability for more cloud providers to be transparent to the subscriber: if they adopt vSphere. Ultimately, this will facilitate vendor agnosticism much like the early days of the Internet. Back then, operators discovered that common protocols allowed for dial-up vendors to share resources in a reciprocal and transparent manner. This allowed the resources of provider A to be utilized by a subscriber of provider B: the end user was completely unaware of the difference. For those that don’t have strict requirements on where their data “lives” and/or are more interested in adherence to availability and SLA requirements, this can actually induce a broader market instead of a narrower one.

If you’ve looked past vRAM, you may have noticed for yourself that vSphere has more to deliver cloud offerings than ever before. VMware will try to convince you that whether cloud bursting, migrating to cloud or expanding hybrid cloud options, having a common underlying architecture promotes better flexibility and reduces overall cost and complexity. They want you to conclude that vSphere 5 is the basis for that architecture. Many will come away from Las Vegas – having seen it – believing it too.

So, as I – and an estimated 20K+ other virtualization junkies – head off to Las Vegas for a week of geek overload, parties and social networking, my thoughts turn to @duncanyp‘s 140+ improvements, enhancements and advances waiting back home in my vSphere 5 lab. Last week he challenged his “followers” to be the first to post examples of all of them; with the myriad of hands-on labs and expert sessions just over the horizon, I hope to do it one better and actually experience them first hand.

These things all add up to a win-win for VMware and a strong showing for VMworld. It’s going to be an exciting and – tip of the hat to @bgracely – industry changing week! Now off to the fray…

References:

See Mike Laverick’s chinwag podcasts

See Chad’s Sakacc’s VirtualGeek blog on stretched cluster issues to overcome

(excuse typos today, wordpress iPad…)

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Short-Take: Nexenta 3.1 Adds VAAI Support, Auto-Sync Resume

August 3, 2011

Nexneta Systems Inc released version 3.1 of its open storage software yesterday with a couple of VMware vSphere-specific feature enhancements. These enhancements are specifically targets at VMware’s vStorage API for Array Integration (VAAI) which promises to accelerate certain “costly” storage operations by pushing their implementation to the storage array instead of the ESX host.

From NexentaStor 3.1 Release Notes, the primitives implemented in 3.1 that contribute to VAAI support include:

  • SCSI Write Same: Supported in vSphere 4.1 and later
    Example. Accelerates zero block writes when creating new virtual disks.
  • SCSI ATS (Atomic Test & Set): Supported in vSphere 4.1 and later.
    Example. Enables specific LUN “region” to be locked instead of entire LUN when cloning a VM.
  • SCSI Block Copy: Supported in vSphere 4.1 and later.
    Example. Avoids reading and writing of block data “through” the ESX host during a block copy operation by allowing VMware to instruct the SAN to do so.
  • SCSI Unmap: Supported in vSphere 5 and later. Enables freed blocks to be returned to the zpool for new allocation when no longer used for VM storage.

Additional “optimizations” and improvements from Nexenta in 3.1 include:

  • In-flight deduplication
  • ARC performance enhancements
  • multiple connections per session for iSCSI
  • DMU fast path for iSCSI (i.e. no extra copy)
  • Auto-sync “resume” with progress bar in GUI/NMV and ability to change source/destination paths OTF
  • Parallel tasks in NMV (i.e. no more busy process “hangs”)
  • Improved CIFS performance
  • Support for multiple DC/DC fail-over for CIFS
  • Better cross-forrest trusts with CIFS
  • Configuration monitoring/reporting via “ConfGuard” plug-in
  • Multiple VIP per service for HA Cluster, fail-over of local users and elimination of separate heartbeat device
  • JBOD management for select devices from within the NMV

Given the addition of VAAI features, the upgrade offers some compelling reasons to make the move to NexentaStor 3.1 and at the same time removes obstacles from choosing NexentaStor as a VMware iSCSI platform for SMB/SME (versus low-end EMC VNXE, which at last look was still waiting on VAAI support.) However, for existing vSphere 4.1+ environments, a word of caution: you will want to “test, test, test” before upgrading to (or enabling) VAAI (fortunately, there’s a NexentaStor VSA available).

Auto-Sync Resume

In the past, NexentaStor’s auto-sync plug-in has been the only integrated means of block replication from one storage pool (or array) to another. In the past, the plug-in allowed for periodic replication events to be scheduled which drew from a marker snapshot until the replication was complete. Upon extended error (where the replication fails), the failure of the replication causes a roll-back to the marker point, eliminating any data that has transferred between the pools. For WAN replication, this can be costly as no check-points are created along the way.

More problematically, there has been no way to recreate a replication service in the event it has been either deleted or missing (i.e. zpool moved to a new host.) This creates a requirement for the replication to start over from scratch – a problem for very large datasets. With Auto-Sync 3.1, later problem is resolved, and provided NexentaStor can find at least one pair of identical snapshots for the file system.

Where I find this new “feature” particularly helpful is in seed replications to external storage devices (i.e. USB2.0 arrays, JBODs, etc.). This allows for a replication to external, removable storage to (1) be completed locally, (2) shipped to a central repository, and (3) a remote replication service created to continue the replication updates over the WAN.

Additionally, consider the case where the above local-to-WAN replication seeding takes place over the course of several months and the hardware at the central repository fails, requiring the replication pool to be moved to another NexentaStor instance. In the past, the limitation on auto-sync would have required a brand new replication set, regardless of the consistency of the replicated data on the relocated pool. Now, a new (replacement) service can be created pointing to the new destination, and auto-sync promises to find the data – intact – and resume the replication updates starting with the last identical marker snapshot.

NexentaStor Native Transport

The default transport for replication in NexentaStor 3.1 is now NexentaStor’s TCP-based Remote Replication protocol (RR). While SSH is still an option for non-NexentaStor destinations, netcat is no longer supported for auto-sync replications. While no indication of performance benefits are available, two tunable parameters are available for RR auto-sync services (per service): TCP connection count (-n) and TCP package size (-P). Defaults for each of these are 4 and 1024, respectively, meaning 4 connections and 1024KB PDU size for the replication session.

Conclusions

For VMware vSphere deployments in SMB, SME and ROBO environments, NexentaStor 3.1 looks to be a good fit, offering high-performance CIFS, NFS, iSCSI and Fiber Channel options in a unified storage environment complete with VAAI support to accelerate vStorage applications. For VMware View installations using NexentaStor, the VAAI/ATS feature should resolve some iSCSI locking behavior issues that have made NFS more attractive but remove SCSI-based VAAI features. That said, with the storage provisioning changes in View 4.5 and upcoming View 5, the ability to pick from FC, iSCSI or NFS (especially at 10G) from within the same storage platform has definite advantages (if not complexity implications.) Suffice to say, NexentaStor’s update is adding more open storage tools to the VMware virtualization architect’s bag of tricks.

NexentaStor 3.1 is available for download now.

Update, 8/12/2011:

Nexenta has found some problems with 3.1 post Q/A. They’ve released this statement on the matter:

Nexenta places the highest importance on maintaining access to and integrity of customer data. The purpose of this Technical Bulletin is to make you aware of an issue with the process of upgrading to 3.1. Nexenta has discovered an issue with the software delivery mechanism we use. This issue can result in errors during the upgrade process and some functionality not being installed properly. Please postpone upgrading to v3.1 until our next Technical Bulletin update. We are actively working to get this corrected and get it back to 100 % service as fast as possible. Until the issue is resolved we have removed 3.1 from the website and suspended upgrades. Thanks for your patience.

Nexenta Support, Aug. 6, 2011

According to sources from within Nexenta, the problems appear to be more related to APT repository/distribution issues “rather than the 3.1 codebase.” All ISO and repository distribution for 3.1 has been pulled until further notice and links to information about 3.1 on the corporate Nexenta site are no longer working…

Update, 8/17/2011:

Today, while working on a follow-up post, the lab systems (virtual storage appliances) were updated to NexentaStor 3.1.1 (both Enterprise and Community editions). Since a question was raised about the applicability of the VAAI enhancements to Community Edition (NexentaStor CE), I’ve got a teaser for you: see the following image of two identical LUNs mounted to an ESXi host from NexentaStor Enterprise Edition (NSEE) and NexentaStor Community Edition (NSCE). If you look closely, you’ll notice they BOTH show “supported” status.

vSphere VMFS5 Datastores provided by NexentaStor Community (VSA04) and Enterprise (VSA03) editions.

Update, 8/19/2011:

Nexenta officially re-released NexentaStor 3.1 today in the form of version 3.1.1 – it is available for download now.