News
6/12/2008
03:05 PM
George Crump
George Crump
Commentary
50%
50%

Flash Vs. RAM Solid State Disks

As major vendors ready for entry into the solid-state disk (SSD) market with Flash memory systems, don't count out the traditional RAM SSD. Even though RAM SSDs are more expensive per capacity, companies like Texas Memory Systems are seeing continued growth in RAM-based SSD systems. Why? RAM SSDs have two advantages: speed and reliability.

As major vendors ready for entry into the solid-state disk (SSD) market with Flash memory systems, don't count out the traditional RAM SSD. Even though RAM SSDs are more expensive per capacity, companies like Texas Memory Systems are seeing continued growth in RAM-based SSD systems. Why? RAM SSDs have two advantages: speed and reliability.In the SSD market, speed is king and for customers needing to squeeze every ounce of I/O out of their systems, RAM SSD is still the only way to go. The answer is in the numbers. For comparison, a typical mechanical hard disk drive does 4- to 5-millisecond reads and writes and can sustain about 150 to 300 random I/O's per second.

The typical Flash SSD completes reads in about 200 microseconds (0.2 milliseconds) and 100,000 random read I/O's per second; very impressive when compared with disk. In read-heavy applications, you will see a significant performance increase. Writes, however, are as high as 2 milliseconds and can sustain up to 25,000 random write I/O's per second. While you will still see a performance increase on writes with some Flash SSD vs. hard disks, they're most impressive from a read-performance perspective.

RAM SSD, on the other hand, is significantly faster at both read and write operations. It performs 15-microsecond (0.015 milliseconds) reads and writes and 400,000 random I/O's per second. Significant performance improvement can be seen on both types of operations. The challenge with RAM SSD is that you are dealing with smaller capacity -- 128 GB is typical, but smaller sizes aren't uncommon. You are looking for applications that have specific files that can be moved to the SSD; redo logs, undo segments, indices, and frequently accessed tables are great examples.

Flash SSD has another write-related issue; it can only handle so many. The typical range for Flash SSD is around 1 million to 5 million write cycles. For most applications, this is many years worth of writes. Most enterprise Flash SSDs are made up of multiple Flash modules. Having multiple Flash modules is essential to delivering maximum bandwidth and high availability through RAID protection. Flash SSDs aren't a good fit for latency-sensitive, write-intensive applications; for example, accelerating redo logs, undo segments, and enterprise messaging.

For many applications, Flash SSDs will offer significant and affordable performance increases, but when you need more performance or have legitimate concerns about a high-write application, RAM SSDs are the way to go.

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
Comments
Newest First  |  Oldest First  |  Threaded View
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: "I've seen worse.  Last week Tim had a dragon."
Current Issue
Security Operations and IT Operations: Finding the Path to Collaboration
A wide gulf has emerged between SOC and NOC teams that's keeping both of them from assuring the confidentiality, integrity, and availability of IT systems. Here's how experts think it should be bridged.
Flash Poll
New Best Practices for Secure App Development
New Best Practices for Secure App Development
The transition from DevOps to SecDevOps is combining with the move toward cloud computing to create new challenges - and new opportunities - for the information security team. Download this report, to learn about the new best practices for secure application development.
Slideshows
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2017-0290
Published: 2017-05-09
NScript in mpengine in Microsoft Malware Protection Engine with Engine Version before 1.1.13704.0, as used in Windows Defender and other products, allows remote attackers to execute arbitrary code or cause a denial of service (type confusion and application crash) via crafted JavaScript code within ...

CVE-2016-10369
Published: 2017-05-08
unixsocket.c in lxterminal through 0.3.0 insecurely uses /tmp for a socket file, allowing a local user to cause a denial of service (preventing terminal launch), or possibly have other impact (bypassing terminal access control).

CVE-2016-8202
Published: 2017-05-08
A privilege escalation vulnerability in Brocade Fibre Channel SAN products running Brocade Fabric OS (FOS) releases earlier than v7.4.1d and v8.0.1b could allow an authenticated attacker to elevate the privileges of user accounts accessing the system via command line interface. With affected version...

CVE-2016-8209
Published: 2017-05-08
Improper checks for unusual or exceptional conditions in Brocade NetIron 05.8.00 and later releases up to and including 06.1.00, when the Management Module is continuously scanned on port 22, may allow attackers to cause a denial of service (crash and reload) of the management module.

CVE-2017-0890
Published: 2017-05-08
Nextcloud Server before 11.0.3 is vulnerable to an inadequate escaping leading to a XSS vulnerability in the search module. To be exploitable a user has to write or paste malicious content into the search dialogue.

Dark Reading Radio
Archived Dark Reading Radio
In past years, security researchers have discovered ways to hack cars, medical devices, automated teller machines, and many other targets. Dark Reading Executive Editor Kelly Jackson Higgins hosts researcher Samy Kamkar and Levi Gundert, vice president of threat intelligence at Recorded Future, to discuss some of 2016's most unusual and creative hacks by white hats, and what these new vulnerabilities might mean for the coming year.