I have been following Virident for a long time (e.g. http://www.mysqlperformanceblog.com/2010/06/15/virident-tachion-new-player-on-flash-pci-e-cards-market/).
They have great PCIe Flash cards based on SLC NAND.
I always thought that Virident needed to come up with an MLC
card, and I am happy to see they have finally done so.
At Virident’s request, I performed an evaluation of their MLC
card to assess how it handles MySQL workload. As I am very
satisfied with the results, I wish to share my findings in this
post.
But first, I wish to offer an overview of the card.
Virident FlashMax Cards are available in 1TB and 1.4TB usable
capacities (the models names are M1000 and M1400)
These specified sizes are already available for end users.
I evaluated M1400 (1.4TB size) model, which I will discuss:
Because Virident has competition in the SSD market, they have stated their goals to distinguish themselves from their competitors:
- Stability of performance: That is to minimize variations in throughput
- Better response times: This is very important for database performance and I appreciate that Virident has made this a priority.
- Performance at full capacity: As we know, SSD-based cards have special characteristics; the throughput declines when space utilization increases. Virident’s design/programming minimizes this decline.
- RAID5 on the card: The card comes with RAID5 support on the card to give better protection.
To deal with a throughput decline, all Flash cards have reserved space. The 1.4TB card, that I have, internally holds 2TB worth of space.
This additional space is used for two purposes:
- 1. To amortize write-intensive workloads, by using additional space.
- 2. To have replacements for failed MLC modules. When one MLC module fails, it is marked as unused, and gets replaced by one from the pool of reserved modules.
Internally, Virident uses 25nm Intel NAND Flash MLC modules, this
is the same technology that Intel uses for the Intel SSD 320
cards. 25nm modules allow the user a greater capacity, Physically
you can place
more GBs into a given area. However, the drawback is that 25nm
has worse reading and writing latencies, compared to previous
generations. However, I have yet to determine how this affects
MySQL workloads.
Virident has provided the following price list:
- M1000 (1000GB Usable) – $13,000
- M1400 (1400GB Usable) – $18,200
- This amounts to $13/GB
Second, it is important to compare the performance of Virident
FlashMAX MLC with available competing solutions.
It is fair to say Fusion-io ioDrive Duo 1.28TB MLC is the most
well-known and most advanced competitor in the market.
I had a chance to administer a head-to-head comparison of
sysbench and tpcc-mysql workloads between FlashMAX 1.4TB and
ioDrive Duo 1.28TB.
It is important to highlight that Fusion-io ioDrive Duo is based
on 34nm NAND technology, which is a full generation behind the
25nm NAND. However at this point, I have no access to Fusion-io
ioDrive2, which is based on 25nm NAND.
Another important factor is that ioDrive Duo is actually two
cards visible in the OS, and the user needs to use a software
RAID. For Virident all 1400GB shows up as one single drive so no
software RAID is necessary.
To compare performances I ran sysbench oltp and tpcc-mysql
benchmarks. I will present the results
for sysbench oltp (with full report available later) below, and
the results for tpcc-mysql in a followup post.
For sysbench, I used our multi-tables sysbench implementation with 256 tables and 10,000,000 rows each. This is a total of around 630GB of data, which allows one to adequately fill both cards in comparison.
Some hardware used in benchmarks include:
- Server: Cisco UCS C250, running Oracle Linux 6.1 and Percona Server 5.5.15
- Client: HP ProLiant DL380 G6, sysbench v5
Of course, our Percona Server was optimized for Flash cards, with
variations for two settings.
I tested combinations of
innodb_buffer_pool_size=120GB, 174GB and
innodb_flush_log_at_trx_commit=1, 2.
The results in this post are for case innodb_buffer_pool_size=174GB and innodb_flush_log_at_trx_commit=1
As in all my recent benchmarks, I use long runs of 1 hour each with measurements every 10 seconds. This methodology allows me to observe trends and the stability of the performance on graphs.
The first graph represents throughput in transactions per second
for different amounts of user threads (more is better). More
concentrated dots represent less variance and better stability of
throughput.
A tabular format, for throughput I use a median of measurements for last 1800 seconds in each run:
| Card / Threads / tps | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | 256 | 512 | 1024 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Fusion-io ioDrive Duo | 83.00 | 177.00 | 322.00 | 523.00 | 644.00 | 740.00 | 801.00 | 798.00 | 761.00 | 784.00 | 162.00 |
| 2 | Virident FlashMAX | 96.00 | 179.00 | 357.00 | 607.00 | 821.00 | 975.00 | 1083.00 | 1156.00 | 1064.00 | 1091.00 | 465.00 |
In order to examine the details of how throughput varies we have
taken 32 threads and examined the timeline graph for each
one:
While you can see that with Virident FlashMAX we have a pretty stable line of around 975 tps, the Fusion-io ioDrive Duo has a variance of 700-800 tps.
My conclusions are as follows:
- It is great to see another player on MLC Flash cards market.
- It is also great that Virident focuses on stability of performance for competitive advantage.
- Beside stability, we also see better throughput in MySQL using the Virident FlashMAX card for every thread count. On 32-64 threads we have about a 35-40% advantage of using Virident FlashMAX.
DISCLOSURE: This review was done as part of our consulting practice for which we compensated by Virident. However, this review was written independently of Virident, and reflects our opinion of this product.