Performance of EMC Clariion AX4

[Rombus]

We are currently using a EdgeStore 2TB usable NAS box. We only

purchased this NAS box for testing purposes with ESX and have found

that things are really slow when running 6VM shared across 2 ESX boxes.

We are now thinking about upgrading the NAS box but the entry level EMC

Clariion has the same usable 2TB and same speed SATA 7500 rpm disks as

the EdgeStore.

The question I am asking is will the speed be any different?

[ThompsG]

Hi,

In order to make a semi-intelligent stab at this would you mind telling us what the drive configurations are between the two devices?

You will probably only see an appreciable increase in speed if your spindle count is higher in one over the other, no matter what fancies are going on inside. There can also be some gains made depening on how you have configured the arrays as well, i.e. RAID type, array sizes, etc.

Thanks,

Glen

[Rodos]

You would expect the AX4 to perform better. You can't change the physics of disk rotation and spindle count however there are ways to drive that hardware and the AX4 will probably do a lot better job of that. For example even a bit of cache is going to make a lot of difference to certain work loads. Speak to the company selling you the AX4 and read the data sheets to get a better understanding.

Rodos

Considering awarding points if this is of use

[ThompsG]

While I am tempted to agree that the AX4 should be expected to perform better, there are serveral important factors to explore. I agree that you cannot change the disk rotation (apart from buying faster disk), however you can change the spindle count. The AX4, I believe can scale to 60 drives by adding 4 expansion enclosures so if you reduced the size of your drives and purchased more smaller ones you will gain quite a lot of speed, or at least this is our experience.

We also tend to see cache as not being that important and in fact depending of workload it is almost benefical to turn it off. Because VMware is generally lots of random I/O you can find that the SAN/NAS spends more time looking in cache then going to disk, therefore adding an unneccessary step. Having said this, I'm not actually brave enough to turn the cache off completely

I totally agree in speaking to the company selling you the AX4 however would be tempted to go one further and ask for a demo unit. This gives you the chance to do your own testing and come up with your own results.

Glen

[Rodos]

Glen, as you have said spindle generally makes a big difference in performance. The point I was trying to make (probably badly) was that even when you have the same spindle count and disk speed, different boxes are going to give you different results simply based on the way they are engineered. A lot of the major vendors SANs are going to be a lot closer in performance, but once you start to move to the bottom of the pack you are going to get bigger difference when you compare to the higher end of town.

For the AX4 the buyer may be able to get a try before you buy or the reseller may have unit for trail if he is lucky. We don't see much of that happening in our market for this size of device.

Considering awarding points if this is of use

[ThompsG]

Agreed. I should have read this into your first answer. Sorry.

Glen

[Rombus]

Thanks for the information. I have checked the specification for the edgestore and it has an Freescale MPC8343 400 mhz CPU and a Promise PDC40719 SATA RAID controller setup in RAID10. The unit only has 128 MB DDR SDRAM and 1 1GB network card. The unit also has 4 1TB SATA HDD 7200 RMP RAID 10.

What I dont understand is if the performance will be similiar is why the NetApp and EMC boxes all have 2GB RAM with Dueal Storage processors if they dont make any differency.

Thanks

[jameran]

Absolutely agreed! I've used several different AX4's, and it is a great platform. Just be sure you have the right type and quantity of drives to get the iops you need.

In a perfect setup, that would mean SAS drives and RAID 1/0... of course, that is more expensive than SATA RAID 5.

[jameran]

RAM is more relevant to the OS the array in running... not the same as write cache.

Dual SP's exist primarily for redundancy... you're not going to be able to do an active/active load balance across them. They are there so that you can keep running with an SP failure.

[RussellCorey]

I had a customer who did a rip and replace of their iSCSI SAN with a fibre channel SAN to improve performance. When we went on site for our first inspection we found that the iSCSI target only had 1 interface connected and his 3 ESX servers were actually on a completely different switch.

Before investing in new storage completely you should see if your current NAS has peaked its bandwidth. If you've actually reached the limitations of the spindles then ignore me because I am a bad person.

[Rodos]

Rombus, you have miss understood me. I am saying that the performance will be better.

Its the total package that counts. Think of your SAN like a car. Cars all have cylinders and use fuel to power them. Most even have the same number of cylinders. They all have the same physical principles of physics at play. But as you know one 2.8l 4c car can go a lot faster than another car of the same spec. Its similar with SANs, why do you think they have differences in price. Now if you are going to by a car and sit in a traffic jam it does not matter how much grunt you have under the hood. You can't really compare SANs base on RAM and CPU speeds. Its the total package that gives the results. Then you have the extra options, like multiple storage processors to give you redundancy, ability to do updates with no outage etc.

Keep reading and asking questions, you are entering a fun and brave new world.

Considering awarding points if this is of use

[ThompsG]

One word, scalability! If you are only driving 4 spindles (2 on write in a RAID10 config) then 2G of RAM and dual SP are not really a happening things, however increase this to 60+ (number plucked from mid air but certainly more than 4) spindles and advantanges start to be seen.

Apart from redundancy on the SP, dual SP's can still benefit you once you scale up (out?) even in a Active/Passive SAN. Within ESX the paths will be set via MRU (Most Recently Used) however you can "fail" paths to make access to various LUN go through different paths, we personally have odd number LUNs going through SPA and even through SPB. Not as elegant as Fixed but does the job. I know this means management, but when you need to gain every last % of horsepower the SAN can deliver, this works.

Also I know this next statement is going to cause all sorts of cries and arguments but with only 4 spindles you are probably better off using RAID5.

Best wishes with your decision.

Glen

[Rombus]

Why RAID 5, I though RAID10 had better performance than RAID 5 and that using RAID 5 was just for if you could not afford the extra disks?

Does anyone know of any cheap storage solutions that are certified by VMware. We are after 4TB usable disk space that can be expangable upto 12TB. We are thinking about using ISCSI or NFS. We have looked at NetApp and EMC but they seem to be really expensive. We have also looked at creating whitebox storage with Openfiler, however Im not sure this will be supported by VMware. The whitebox solution does sound good though as it would only cost us around £2000

Any ideas?

Thanks for the help

[jameran]

A great, and less expensive, alternative is Lefthand Networks. They are fully supported and their products work very well.

[Rombus]

Whats the estimated price for an entry level Lefthand SAN?

The NSM 2120 with 6TB usable SATA drives.

[maethlin4]

I keep reading people talk about Lefthand as a "less expensive" solution.

I've read great things about them, and like their tech on paper. Yet, I have yet to see any Lefthand pricing that is anywhere near affordable for large amounts of storage.

It's always something like$70-100k for 12TB raw capacity. Unless all the prices I've seen are just wrong (possible, since pricing is always infuriatingly hard to get for any decent enterprise storage), then this does not qualify as "less expensive" unless compared to already-overpriced gear from the likes of EMC, NetApp, etc.

Don't get me wrong - if you have money to burn, those solutions are great.

But when people come asking for options on these forums, they're usually looking for really reasonably priced, relaible gear.

By the way, to that end, the stuff I personally have experience with is Infortrend. They're the biggest raid array makers you've never heard of (they used to OEM all their stuff to the likes of Sun and Quantum) and their stuff seems quite solid. I've used a lot of their FC stuff in the past, never had a failure. Check CDW for pricing - you can probably do even better than that if you bargained hard with some other resellers. I have yet to see other solutions as cheap and dependable as Infortrend, but if anyone else has - feel free to share the info, I'm always on the lookout for good value in storage.

[JohnADCO]

I agree, cost / available budget drive the model of SAN purchased more than anything else.

I mean, 45tb on the cheap with something like an MD3000i.