Test Blade Configuration

Our bladecenters are full of high performance blades that we use to run a virtualized hosting environment at this time. Since the blades that are in those systems are in production, we couldn’t very well use them to test the performance of our ZFS system. As such, we had to build another blade. We wanted the blade to be similar in spec to the blades that we were using, but we also wanted to utilize some of the new technology that has come out since we put many of our blades into production. Our current environment is mixed with blades that are running Dual Xeon 5420 processors w/ 32GB RAM and dual 250GB SATA hard drives, some systems that are running Dual Xeon 5520 processors w/48GB RAM and dual 32GB SAS HDD’s.  We use the RAID1 volumes in each blade as boot volumes. All of our content is stored on RAID10 SANs.

Following that tradition we decided to use the SuperMicro SBI-7126T-S6 as our base blade. We populated it with Dual Xeon 5620 processors (Intel Xeon Nehalem/Westmere based 32nm quad core), 48GB Registered ECC DDR3 memory, dual Intel X-25V SSD drives (for boot in a RAID1 mirror) and a SuperMicro AOC-IBH-XDD InfiniBand Mezzanine card.

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Front panel of the SBI-7126T-S6 Blade Module

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Intel X25-V SSD boot drives installed

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Dual Xeon 5620 processors, 48GB Registered ECC DDR3 memory, Infiniband DDR Mezzanine card installed

Our tests will be run using Windows 2008R2 and Iometer. We will be testing iSCSI connections over gigabit Ethernet, as this is what most budget SAN builds are based around.  Our blades also offer us connectivity options in the form of 10Gb Ethernet and 20Gb Infiniband but those connections are out of the scope of this article.

Price OpenSolaris box

 The OpenSolaris box, as tested was quite inexpensive for the amount of hardware added to it.  Overall costs for the OpenSolaris system was $6765.  The breakdown is here :

Price of Nexenta

 While OpenSolaris is completely free, Nexenta is a bit different, as there are software costs to consider when building a Nexenta system.  There are three versions of Nexenta you can choose from if you decide to use Nexenta instead of OpenSolaris.  The first is Nexenta Core Platform, which allows unlimited storage, but does not have the GUI interface.  The second is Nexenta Community Edition, which supports up to 12TB of storage and a subset of the features.  The third is their high end solution, Nexenta Enterprise.  Nexenta Enterprise is a paid-for product that has a broad feature set and support, accompanied by a price tag.

The hardware costs for the Nexenta system are identical to the OpenSolaris system.  We opted for the trial Enterprise license for testing (unlimited storage, 45 days) as we have 18TB of billable storage.  Nexenta charges you based on the number of TB that you have in your storage array.  As configured the Nexenta license for our system would cost $3090, bringing the total cost of a Nexenta Enterprise licensed system to $9855.

Price of Promise box

The Promise M610i is relatively simple to calculate costs on.  You have the cost of the chassis, and the cost of the drives.  The breakdown of those costs is below.

How we tested with Iometer

Our tests are all run from Iometer, using a custom configuration of Iometer.  The .icf configuration file can be found here.  We ran the following tests, starting at a queue depth of 9, ending with a queue depth of 33, stepping by a queue depth of 3.  This allows us to run tests starting below a queue depth of 1 per drive, to a queue depth of around 2 per drive (depending on the storage system being tested).

The tests were run in this order, and each test was run for 3 minutes at each queue depth.

4k Sequential Read

4k Random Write

4k Random 67% write 33% read

4k Random Read

8k Random Read

8k Sequential Read

8k Random Write

8k Random 67% Write 33% Read

16k Random 67% Write 33% Read

16k Random Write

16k Sequential Read

16k Random Read

32k Random 67% Write 33% Read

32k Random Read

32k Sequential Read

32k Random Write

These tests were not organized in any particular order to bias the tests.  We created the profile, and then ran it against each system.  Before testing, a 300GB iSCSI target was created on each system.  Once the iSCSI target was created, it was formatted with NTFS defaults, and then Iometer was started.  Iometer created a 25GB working set, and then started running the tests.

While running these tests, bear in mind that the longer the tests run, the better the performance should be on the OpenSolaris and Nexenta systems.  This is due to the L2ARC caching.  The L2ARC populates slowly to reduce the amount of wear on MLC SSD drives (approximately 7MB/sec).  When you run a test over a significant amount of time the caching should improve the number of IOPS that the OpenSolaris and Nexenta systems are able to achieve.