Category Archives: HP

Solid State Storage: Enterprise State Of Affairs

Here In A Flash!

Its been a crazy last few years in the flash storage space. Things really started taking off around 2006 when NAND flash and moores law got together. in 2010 it was clear that flash storage was going to be a major part of your storage makeup in the future. It may not be NAND flash specifically though. It will be some kind of memory and not spinning disks.

Breaking The Cost Barrier.

For the last few years, I’ve always told people to price out on the cost of IO not the cost of storage. Buying flash storage was mainly a niche product solving a niche problem like to speed up random IO heavy tasks. With the cost of flash storage at or below standard disk based SAN storage with all the same connectivity features and the same software features I think it’s time to put flash storage on the same playing field as our old stalwart SAN solutions.

Right now at the end of 2012, you can get a large amount of flash storage. There is still this perception that it is too expensive and too risky to build out all flash storage arrays. I am here to prove at least cost isn’t as limiting a factor as you may believe. Traditional SAN storage can run you from 5 dollars a Gigabyte to 30 dollars a Gigabyte for spinning disks. You can easily get into an all flash array in that same range.

Here’s Looking At You Flash.

This is a short list of flash vendors currently on the market. I’ve thrown in a couple non-SAN types and a couple traditional SAN’s that have integrated flash storage in them. Please, don’t email me complaining that X vendor didn’t make this list or that Y vendor has different pricing. All the pricing numbers were gathered from published sources on the internet. These sources include, the vendors own website, published costs from TPC executive summaries and official third party price listings. If you are a vendor and don’t like the prices listed here then publicly publish your price list.

There are always two cost metrics I look at dollars per Gigabyte in raw capacity and dollars per Gigabyte in usable capacity. The first number is pretty straight forward. The second metric can get tricky in a hurry. On a disk based SAN that pretty much comes down to what RAID or protection scheme you use. Flash storage almost always introduces deduplication and compression which can muddy the waters a bit.

Fibre Channel/iSCSI vendor list

Nimbus Data

Appearing on the scene in 2006, they have two products currently on the market. the S-Class storage array and the E-Class storage array.

The S-Class seems to be their lower end entry but does come with an impressive software suite. It does provide 10GbE and Fibre Channel connectivity. Looking around at the cost for the S-Class I found a 2.5TB model for 25,000 dollars. That comes out to 9.7 dollars per Gigabyte in raw space. The S-Class is their super scaleable and totally redundant unit. I found a couple of quotes that put it in at 10.oo dollars a Gigabyte of raw storage. Already we have a contender!

Pure Storage

In 2009 Pure Storage started selling their flash only storage solutions. They include deduplication and compression in all their arrays and include that in the cost per Gigabyte. I personally find this a bit fishy since I always like to test with incompressible data as a worst case for any array. This would also drive up their cost. They claim between 5.00 and 10.00 dollars per usable Gigabyte and I haven’t found any solid source for public pricing on their array yet to dispute or confirm this number. They also have a generic “compare us” page on their website that at best is misleading and at worst plain lies. Since they don’t call out any specific vendor in their comparison page its hard to pin them for falsehoods but you can read between the lines.

Violin Memory

Violin Memory started in earnest around 2005 selling not just flash based but memory based arrays. Very quickly they transitioned to all flash arrays. They have two solutions on the market today. The 3000 series which allows some basic SAN style setups but also has direct attachments via external PCIe channels. It comes in at 10.50 dollars a Gigabyte raw and 12 dollars a Gigabyte usable. The 6000 series is their flagship product and the pricing reflects it. At 18.00 dollars per Gigabyte raw it is getting up there on the price scale. Again, not the cheapest but they are well established and have been used and are resold by HP.

Texas Memory Systems/IBM

If you haven’t heard, TMS was recently purchased by IBM. Based in Houston, TX I’ve always had a soft spot for them. They were also the first non-disk based storage solution I ever used. The first time I put a RamSan in and got 200,000 IO’s out of the little box I was sold. Of course it was only 64 Gigabytes of space and cost a small fortune. Today they have a solid flash based fibre attached and iSCSI attached lignup. I couldn’t find any pricing on the current flagship RamSan 820 but the 620 has been used in TPC benchmarks and is still in circulation. It is a heavy weight at 33.30 dollars a Gigabyte of raw storage.

Skyera

A new entrant into this space they are boasting some serious cost savings. They claim a 3.00 dollar per Gigabyte usable on their currently shipping product. The unit also includes options for deduplication and compression which can drive the cost down even further. It is also a half depth 1U solution with a built-in 10GbE switch. They are working on a fault tolerant unit due out second half of next year that will up the price a bit but add Fibre Channel connectivity. They have a solid pedigree as they are made up of the guys that brought the Sanforce controllers to market. They aren’t a proven company yet, and I haven’t seen a unit or been granted access to one ether. Still, I’d keep eye on them. At those price points and the crazy small footprint it may be worth taking a risk on them.

IBM

I’m putting the DS3524 on a separate entry to give you some contrast. This is a traditional SAN frame that has been populated with all SSD drives. With 112 200 GB drives and a total cost of 702908.00 it comes in at 31.00 a Gigabyte of raw storage. On the higher end but still in the price range I generally look to stay in.

SUN/Oracle

I couldn’t resist putting in a Sun F5100 in the mix. at 3,099,000.00 dollars it is the most expensive array I found listed. It has 38.4 Terabytes of raw capacity giving us a 80.00 dollars per Gigabyte price tag. Yikes!

Dell EqualLogic

When the 3Par deal fell apart Dell quickly gobbled up EqualLogic, a SAN manufacturer that focused on iSCSI solutions. This isn’t a flash array. I wanted to add it as contrast to the rest of the list. I found a 5.4 Terabyte array with a 7.00 dollar per Gigabyte raw storage price tag. Not horrible but still more expensive that some of our all flash solutions.

Fusion-io

What list would be complete without including the current king of the PCIe flash hill Fusion-io. I found a retail price listing for their 640 Gigabyte Duo card at 19,000 dollars giving us a 29.00 per usable Gigabyte. Looking at the next lowest card the 320 Gigabyte Duo at 7495.00 dollars ups the price to 32.20 per useable Gigabyte. They are wicked fast though :)

So Now What?

Armed with a bit of knowledge you can go forth and convince your boss and storage team that a SAN array fully based on flash is totally doable from a cost perspective. It may mean taking a bit of a risk but the rewards can be huge.

 

When Technical Support Fails You – UPDATE and Answers!

As promised and update on what has happened so far. A correction needs to be made. the P800 is a PCIe 1.0 card so the bandwidth is cut in half from 4GB/sec to 2GB/sec.

My CDW rep did get me in contact with an HP technical rep who actually knew something about the hardware in question and its capabilities. It was one of those good news, bad news situations. We will start with the bad news. The performance isn’t off. My worst fears were confirmed.

The Hard Disks

The HP Guy (changing the names to protect the innocent) told me their rule of thumb for the performance of the 2.5” 73GB 15K drives is 10MB/Sec. I know what you are thinking, NO WAY! But, I’m not surprised at all. What I was told is the drives ship with the on board write cache disabled. They do this for data integrity reasons. Since the cache on the drive isn’t battery backed if there was any kind of failure the potential for data loss is there. There are three measurements of hard disk throughput, disk to cache, cache to system and disk to system. Disk to cache is how fast data can be transferred from the internal data cache to the disk usually sequentially. On our 15k drive this should be on average 80MB/sec. Disk to system, also referred to burst speed, is almost always as fast as our connection type. Since we are using SAS that will be close to 250MB/sec. Disk to system is no caching at all. Without the cache several IO reordering schemes aren’t used, there is no buffer between you and the system, so you are effectively limited by the Areal Density and the rotational speed of the disk. This gets us down to 10 to 15 megabytes a second. Write caching has a huge impact on performance. I hear you saying the controller has a battery backed cache on it, and you would be right.

The Disk Controller

The P800 controller was the top of the line that HP had for quite a while. It is showing its age now though. The most cache you can get at the moment is 512MB. It is battery backed so if there is a sudden loss of power the data in cache will stay there for as long as the battery holds out. When the system comes back on the controller will attempt a flush to disk. The problem with this scheme is two fold. The cache is effectively shared across all your drives since I have 50 drives total attached to the system that is around 10.5 megabytes per drive. Comparable drives ship with 16 to 32 megabytes of cache on them normally. The second problem is the controller can’t offload the IO sorting algorithms to the disk drive effectively limiting it’s throughput. It does support native command queuing and elevator sorting but applied at the controller level just isn’t as fast as at the disk level.If I had configured this array as a RAID 6 stripe the loss of performance from that would have masked the other bottlenecks in the controller. Since I’ve got this in a RAID 10 the bottleneck is hit much sooner with fewer drives. On the P800 this limit appears to be between 16 and 32 disks. I won’t know until I do some additional testing.

Its All My Fault

If you have been following my blog or coming to the CACTUSS meetings you know I tell you to test before you go into production. With the lack of documentation I went with a set of assumptions that weren’t valid in this situation. At that point I should have stopped and done the testing my self. In a perfect world I would have setup the system in a test lab run a series of controlled IO workloads and come up with the optimal configuration. I didn’t do as much testing as normal and now I’m paying the price for that. I will have to bring a system out of production as I run benchmarks to find the performance bottlenecks.

The Good News

I have two P800’s in the system and will try moving one of the MSA70’s to the other controller. This will also allow me to test overall system performance across multiple PCIe busses. I have another system that is an exact duplicate of this one and originally had the storage configured in this way but ran into some odd issues with performance as well.

HP has a faster external only controller out right now the P411. This controller supports the new SASII 6G protocols, has faster cache memory and is PCIe 2.0 complainant. I am told it also has a faster IO processor as well. We will be testing these newer controllers out soon. Also, there is a replacement for the P800 coming out next year as well. Since we are only using external chassis with this card the P411 may be a better fit.

We are also exploring a Fusion-io option for our tempdb space. We have an odd workload and tempdb accounts for half of our write operations on disk. Speeding up this aspect of the system and moving tempdb completely away from the data we should see a marked improvement over all.

Lessons Learned or Relearned

Faced with the lack of documentation, don’t make assumptions based on past experiences. Test your setup thoroughly. If you aren’t getting the information you need, try different avenues early. Don’t assume your hardware vendor has all the information. In my case, HP doesn’t tell you that the disks come with the write cache disabled. They also don’t give you the full performance specifications for their disk controllers. Not even my HP Guy had that information. We talked about how there was much more detailed information on the EVA SAN than there was on the P800.

Now What?

Again, I can’t tell you how awesome CDW was in this case. My rep, Dustin Wood, went above and beyond to get me as much help as he could, and in the end was a great help. It saddens me I couldn’t get this level of support directly from HP technical support. You can rest assured I will be giving HP feedback to that effect. By not giving the customer and even their own people all the information sets everyone up for failure.

I’m not done yet. There is a lot of work ahead of me, but at least I have some answers.You can bet I’ll be over at booth #414 next week at PASS asking HP some hard questions!

When Technical Support Fails You

I have had the pleasure of being a vendor, and technical support for both hardware and software products. I know it isn’t easy. I know it isn’t always possible to fix everything. The level of support I’ve received from HP on my current issue is just unacceptable. This is made more frustrating by the lack of documentation. The technical documents show capacity. How many drives in an array, Maximum volume size but nothing on throughput.Every benchmark they have seems to be relative to another product with no hard numbers. For example, the P800 is 30% faster than the previous generation.

I’m not working with a complicated system. It’s a DL380 G5 with a P800 and two MSA70’s fully populated with 15k 73GB hard drives. 46 of them are in a RAID 10 array with 128k stripe. Formatted it NTFS with a 64k block size and sector aligned the partition. Read/Write cache is set at 25%/75%. This server originally just had one MSA70. We added the second for capacity expansion and expected to see a boost in performance as well. As you can probably guess, there wasn’t any increase in performance at all.

Here is what I have as far as numbers. Some of these are guesses based on similar products.

P800 using two external miniSAS 4x connectors maximum throughput of 2400 MB/sec (2400Mbit per link x 4 per connector x 2 connectors).
The P800 uses a PCIe x8 connection to the system at 4,000 MB/Sec (PCIe 2.0 2.5GHz 4GB/sec each direction).
Attached to the controller are 15k 73GB 2.5” hard drives 46 of them for a raw speed 3680 MB/Sec of sequential read or write speed (23x80MB/sec write sequential 2 MSA70’s RAID 10 46 Drives total based on Seagate 2.5 73GB SAS 15.1k)

Expected write speed should be around 1200 megabytes a second.

We get around 320 MB/Sec sequential write speed and 750MB/sec in reads.

Ouch.

Did I mention I also have a MSA60 with 8 7.2k 500GB SATA drives that burst to 600MB/sec and sustain 160MB/Sec writes in a RAID 10 array? Yeah, something is rotten in the state of Denmark.

With no other options before me I picked up the phone and called.

I go through HP’s automated phone system, which isn’t that painful at all, to get to storage support. Hold times in queue were very acceptable. A level one technician picked up the call and started the normal run of questions. It only took about 2 minutes to realize the L1 didn’t understand my issue and quickly told me that they don’t fix performance issues period. He told me to update the driver, firmware, and reboot. Of course none of that had worked the first time but what the heck, I’ll give it the old college try. Since this is a production system I am limited on when I can just do these kinds of things. This imposed lag makes it very difficult to keep an L1 just sitting on the phone for five or so hours on hold while they wait for me to complete the assigned tasks. I let him go with the initial action plan in place with an agreement that he would follow up.Twice I got automated emails that the L1 had tried to call and left voicemails for me. Twice, there were no voicemails. I sent him my numbers again just to be on the safe side. Next, I was told to run the standard Array Diagnostic Utility and a separate utility that they send you to gather all the system information and logs, think a PSSDiag or SQLDiag. After reviewing the logs he didn’t se anything wrong and had me update the array configuration utility. I was then told they would do a deeper examination of the logs I had sent and get back to me. Three days later I got another email saying the L1 had tried to call and left me a message. Again there was no voicemail on my cell or my desk phone. I sent a note back to the automated system only to find the case had been closed!

I called back in to the queue and gave the L1 who answered my case number, he of course told me it was closed. He read the case notes to me, the previous L1 had logged it as a network issue and closed the case. If I had been copying files over the network and not to another local array I can see why it had been logged that way. I asked to open a new case and to speak to a manager. I was then told the manager was in a meeting. No problem, I’ll stay on the line. After 45 minutes I was disconnected. Not one to be deterred, I called back again. The L1 that answered was professional and understanding. Again, I was put on hold while I waited for the manager to come out of his meeting. About 10 minutes later I was talking to him. He apologized and told me my issues would be addressed.

I now had a new case number and a new L1. Again, we dumped the diagnostic logs and started from the beginning. This time he saw things that weren’t right. There was a new firmware for the hard drives, a new driver for the P800, and a drive that was showing some errors. Finally, I felt like I was getting somewhere! At this point it has been ten days since I opened the previous case. We did another round of updates. A new drive was dispatched and installed. The L1 did call back and actually managed to ether talk to me or leave a message. When nothing had made any improvement he went silent. I added another note to the case requesting escalation.

That was eight days ago. At this point I have sent seven sets of diagnostic logs. Spent several hours on the phone. And worked after hours for several days. The last time I talked to my L1, the L2’s were refusing to accept the escalation. It was clearly a performance problem and they don’t cover that. The problem is, I agree. Through this whole process I have begged for additional documentation on configuration and setup options, something that would help me configure the array for maximum performance.

They do offer a higher level of support that covers performance issues, for a fee of course. This isn’t a cluster or a SAN. It is a basic setup in every way. The GUI walks you through the setup, click, click, click, monster RAID 10 array done. What would this next level of paid support tell me?

My last hope is CDW will be able to come through with documentation or someone I can talk to. They have been very understanding and responsive through this whole ordeal.

Thirty one days later, I’ve still got the same issue. I now have ordered enough drives to fill up the MSA60. The plan is to transfer enough data to free up one of the MSA70’s. Through trial and error, I will figure out what the optimum configuration is. Once I do I’ll post up my findings here.

If any of you out there in internet-land have any suggestions I’m all ears.