News
11/7/2008
08:52 AM
George Crump
George Crump
Commentary
Connect Directly
RSS
E-Mail
50%
50%

SSD's Latency Impact

In our last entry we talked about latency and what it was. We also discussed how storage system manufacturers are trying to overcome latency and performance issues of mechanical drives by using techniques like making the drives faster by using higher RPM drives, array groups with a high drive count, short-stroking those drives, wide striping those drives, and increasing the number of application servers

In our last entry we talked about latency and what it was. We also discussed how storage system manufacturers are trying to overcome latency and performance issues of mechanical drives by using techniques like making the drives faster by using higher RPM drives, array groups with a high drive count, short-stroking those drives, wide striping those drives, and increasing the number of application servers for improved parallelism.All of these techniques cost money, are not very green, and in many cases are more expensive than simply using SSD. Not to mention that they don't typically come close to SSD performance. The result has been the existence of standalone, purpose-built SSD solutions like those from Texas Memory Systems, Solid Data Systems, and Violin Memory, or the manufacturer adding SSD in a "drive-like" manner to its current storage systems.

The speed of SSD technology, especially DRAM, changes the latency focus away from the actual storage medium, as it has now been optimized, and onto the storage system's infrastructure, which is suddenly a lot slower than the storage media. For vendors that incorporate SSD into existing drive enclosures, the performance of the shelf itself becomes a problem, the performance of the processors in the controllers becomes a problem, and an incorrectly sized cache (too big or too small) becomes a problem.

Another factor is that the software load on the controller becomes an issue. For the past several years, storage manufacturers have been piling on features to the storage controller like snapshots, replication, data deduplication, and others. All of these features take computing resources away from responding to storage I/O requests, which worsens system latency.

The result is that while the SSD technology going into the solution may be fast, simply adding SSD to your storage system may not dramatically improve performance like it should. Standalone, purpose-built SSD systems offer lower latency because these vendors have built systems from the chip up that are designed to deliver on the low latency of SSD.

In our next entry, we will examine those differences and how storage manufacturers will need to alter their delivery of SSD technology. Then we will wrap up with capacity management on SSDs. At the cost of SSD technology, the only good SSD is a FULL SSD.

Join us for our upcoming Webcast SSD: Flash vs. DRAM...and the winner is?

Track us on Twitter: http://twitter.com/storageswiss.

Subscribe to our RSS feed.

George Crump is founder of Storage Switzerland, an analyst firm focused on the virtualization and storage marketplaces. It provides strategic consulting and analysis to storage users, suppliers, and integrators. An industry veteran of more than 25 years, Crump has held engineering and sales positions at various IT industry manufacturers and integrators. Prior to Storage Switzerland, he was CTO at one of the nation's largest integrators.

Comment  | 
Print  | 
More Insights
Register for Dark Reading Newsletters
White Papers
Flash Poll
Current Issue
Cartoon
Threat Intel Today
Threat Intel Today
The 397 respondents to our new survey buy into using intel to stay ahead of attackers: 85% say threat intelligence plays some role in their IT security strategies, and many of them subscribe to two or more third-party feeds; 10% leverage five or more.
Video
Slideshows
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2013-6306
Published: 2014-08-22
Unspecified vulnerability on IBM Power 7 Systems 740 before 740.70 01Ax740_121, 760 before 760.40 Ax760_078, and 770 before 770.30 01Ax770_062 allows local users to gain Service Processor privileges via unknown vectors.

CVE-2014-0232
Published: 2014-08-22
Multiple cross-site scripting (XSS) vulnerabilities in framework/common/webcommon/includes/messages.ftl in Apache OFBiz 11.04.01 before 11.04.05 and 12.04.01 before 12.04.04 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors, which are not properly handled in a (1)...

CVE-2014-3525
Published: 2014-08-22
Unspecified vulnerability in Apache Traffic Server 4.2.1.1 and 5.x before 5.0.1 has unknown impact and attack vectors, possibly related to health checks.

CVE-2014-3563
Published: 2014-08-22
Multiple unspecified vulnerabilities in Salt (aka SaltStack) before 2014.1.10 allow local users to have an unspecified impact via vectors related to temporary file creation in (1) seed.py, (2) salt-ssh, or (3) salt-cloud.

CVE-2014-3587
Published: 2014-08-22
Integer overflow in the cdf_read_property_info function in cdf.c in file through 5.19, as used in the Fileinfo component in PHP before 5.4.32 and 5.5.x before 5.5.16, allows remote attackers to cause a denial of service (application crash) via a crafted CDF file. NOTE: this vulnerability exists bec...

Best of the Web
Dark Reading Radio
Archived Dark Reading Radio
Three interviews on critical embedded systems and security, recorded at Black Hat 2014 in Las Vegas.