07 Jan

What you can expect from SSD?

Hard disk performance is limited by mechanical parts velocity and there is no solution for this issue.

Servers are using RAID for redundancy and for performance. Thanks to RAID technology it is possible to scale single hard disk performance.

The team of disks works faster, but applications are needing increased improvements as over periods technical evolutions.

There are storage offers using DDR RAM or SLC Flash that claim 2-20 GB/s throughput or 100K to millions of random IO/sec

But the cost of such systems are extremely high.

Recently RAID controller vendors like LSI and Adaptec offer SSD cache options. If the applications require higher random IO/sec such solutions are worth looking into.

Adaptec claims 8 times faster IO than HDD-only arrays.

LSI claims even 50 times faster IO. They have simulated web servers that re-read hot spot activity. With CacheCade enabled reached at 14,896 IO/sec and compared to 273 IO/sec with disabled CacheCade.

Such SATA/SSD hybrid can significantly  improve applications with random IO patterns. They work with single SSD as a minimum , the solution is relatively inexpensive.

Adaptec maxCache™ 64GB SSD Cache Performance Kit SRP = $1,795

And  LSI CacheCade software pack has a suggested retail price of $270 plus X25-E Extreme 64GB cost $700 makes about $1,000.

Very interesting will be to know what kind of random IO/ps can be reached if we use SSD only.  We have created RAID 5 with 4 * INTEL X25-M SATA SSD. The RAID 5 was fully initialized then the IOmeter test was started.

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