Storevirtual VSA Version 11.

[johnlong]

Any word on how this new version will play with B&R version 7?

Here's a good article on the VAS v.11
http://vmfocus.com/2013/08/16/whats-new ... d-os-11-0/

[Gostev]

I've asked QC. Will update once I hear back from them.

[Gostev]

QC said they did perform a smoke test with VSA v11 when it was released, and observed no issues.

[dellock6]

Honestly, I would suppose the new tiering mechanism is completely internal to the VSA, and the output result is still a iSCSI LUN that can be reached via the virtual IP address. I did some "smoke tests" too even with the Beta, and the behaviour of the VSA from the outside is basically the same of the 10.5, "only" way faster with the SSD addition
Storage snapshots removal would surely benefit from the new SSD support!

Luca.

[johnlong]

Good info guys.

I'm getting a test server ready.

I'm really excited about the tiered storage to SSD's also. That means I won't have to upgrade my array controllers which are already very good, areca 1882ix 16 port, which oddly enough don't have SSD caching. I wonder how the HP sotrage tiering works though, is it caching or is it storing one copy of the data to the SSD and moving less frequently used data off the SSD. Also can you specify where a lun is created? Right now you just throw a bunch of storage at it in the form of vmdk's and it chooses where to store the data. Lots of questions and lots of testing to do! I'll probably pickup a cheap SSD for testing purposes also.

I think I'll stick with enterprise sata ssd's though, due to price. Although I may look at samsung 840 pro, after reading this. http://us.hardware.info/reviews/4178/ha ... conclusion

I'll probably go with 2 SSD's either a 256 or 512 gb in a raid 1. Should be pretty smoking fast.

[tsightler]

I use the Samsung 840 Pro for the SSD caching layer in my home lab setup. It's fine for that purpose, but I wouldn't recommend it for any real workload. Sure, it might last, but it's latencies are all over the board, especially with a decent read/write mix. You'll almost certainly be better off with a real enterprise SSD even if it's smaller. Just my opinion and YMMV.

[johnlong]

Just realized the 840 pro uses MLC and the 840 in that link uses TLC. Cool review nevertheless. I'll still consider the 840 pro though.

[dellock6]

John, two answers for you.

-SSD: forget the Samsung disks on a storage array! They are really cool for desktops, I too use them both in my laptop and in my lab, but I would NEVER use them in a production storage. Two main reason: unpredictable performances when at steady state (near full and their controller needs to run wear leveling/garbage collection and free cells for new data) and most of all endurance, that is low on this disks. Tiered VSA is not going to use SSDs as cache, but as a proper tier. This means SSDs will be hit by large amounts of writes, thus reducing SSD life. Use enteprise SSDs like for example Intel DCS 3700, they guarantee 10x writes as their size "daily" fo 5 years.

- VSA Tier: is going to work as the actual system, basically you will create a new virtual disk based on the SSD disks, and then map the vmdk to the VSA. Then, inside the CMC, you will need to configure this virtual disk as "tier 0", that is the higher tier. Usual virtual disks will be configured as Tier 1. Once you have two tiers, adaptive optimizaion will be enabled. The VSA does not uses any information coming from the hardware, so you will have to manually place vmdks above the SSDs. And since it's a vmdk holding data and not a simple cache, you would need at least 2 * SSDs configured in raid1 via the underlying controller to guarantee data protection.

[shameless plug] I wrote a quick review about how the tiering works in my blog: http://www.virtualtothecore.com/en/news-lefthand-11/

Luca.

[johnlong]

I enjoyed reading your blog entry. I also see what you mean about not using consumer grade SSD's. Enterprise SSD's have more reserve capacity and higher levels of redundancy built in for higher reliability and sustained performance. But they cost a lot more money, though in the long run they are worth it because I won't have to replace it as often. At least that is the hope!

[dellock6]

Well, even if you will have to replace them, you will still have an underlying raid protecting the overall SSD tier, and thanks to the 5 years guarantee, replacement will come free of charge. You will probably change them before the end of the guarantee due to new technologies that will surely come out in the next years.

Luca.

[Fiskepudding]

Although this has nothing directly to do with VSA, I would just like to comment on the SSD part.

John, two answers for you.
-SSD: forget the Samsung disks on a storage array! They are really cool for desktops, I too use them both in my laptop and in my lab, but I would NEVER use them in a production storage. Two main reason: unpredictable performances when at steady state (near full and their controller needs to run wear leveling/garbage collection and free cells for new data) and most of all endurance, that is low on this disks. Tiered VSA is not going to use SSDs as cache, but as a proper tier. This means SSDs will be hit by large amounts of writes, thus reducing SSD life. Use enteprise SSDs like for example Intel DCS 3700, they guarantee 10x writes as their size "daily" fo 5 years.
Luca.

Luca, i agree with you, it is not recommended.
But we actually run consumer SSD's on two hosts in our production environment.
Our first attempt failed after 1 year. We then used Crucial M4 disks. We also used a lot of the same disks on workstations.
After a few months we saw boot problems and crashes with the M4 disks on the workstations, and then after a few days a non-bootable system.
We narrowed the problem down to an Intel chipset in combo with the M4...

On one host with Crucial M4's we had a total failure on the RAID6 after 1 year.
We swapped the disks to Samsung on this host, and as a precaution we also changed to Samsung on the other host as well.
(All disks were credited by our supplier.)

The Samsung’s has served us very well for 1,5 years (knock on wood). Not one disk changed.
HOST1: 14 x 512GB disk RAID6 + Spare ~ 5 TB, Latency averages about 0,011 ms.
HOST2: 22 x 512GB disk RAID6 + Spare ~ 9 TB, Latency averages about 0,05 ms.
I would, like Luca, never recommend this to anyone. But if you can life with the risks, YOU might consider it. But _I_ never recommended it .

On three other hosts we have HP 100GB SSD’s but they cost 10 times what the Samsung 512 does…So that’s makes them about 50 times as expensive pr GB.
So we felt it was worth the risk. But it is a long way from us accepting the risk, to recommend this to anyone.

[dellock6]

Oh, the Crucial M4.... I've been hit by the infamous 5184 hrs bug last year, it was painful to say the least...

I know HP SSDs are totally crazy on price, exactly as any other SSD from a storage vendor, but there are alternatives. In Italy an Intel 3700 comes at 200 € for 100 GB, is not that much, especially if you think about its performances. And is way better than any consumer SSD.

We are talking about a storage tier, so data is going to stay committed on those SSDs, I would not gamble honestly.
Caching is a completely different story, data is not permament on them so you can accept the risk...

Luca.