It’s been 35 years since the very first solid-state drive (SSD) was launched. This went by the name “solid-state disk”. These were called “solid-state” because they contained no moving parts and only had memory chips. This storage medium was not magnetic or optical, but they were solid state semiconductors such as battery-backed RAM, RRAM, PRAM or other electrically erasable RAM-like non-volatile memory chips.
In terms of benefits, SSDs worked faster than a traditional hard drive could in data storage and retrieval – but this came at a steep cost. It’s been a constant quest in the industry, over the years, to make the technology of SSD cheaper, smaller, and faster in operation, with higher storage capacity. A post in StorageSearch.com shows the development and transformation of SSD, over the years, since its first usage and availability until now.
Why Storage and Datacenter Admins Should Care?
More than the user using the PC or notebook, it’s the storage admins who are spending time managing and troubleshooting the drives for detecting storage hotspots and other performance issues. And it’s imperative that storage and datacenter admins understand the SSD technology so they can better apply and leverage the technology in managing the datacenter.
Application #1 – Boosting Cache to Improve Array I/O
A cache is a temporary storage placed in front of the primary storage device to make the storage I/O operations faster and transparent. When an application or process tries to access the data stored in the cache, this can be read and written much quicker than from the primary storage device which could be a lot slower. All modern arrays have a built-in cache, but SSD can be leveraged to “expand” this cache, thus speeding up all I/O requests to the array. Although this approach has no way to distinguish between critical and non-critical I/O, it has the advantage of improving performance for all applications using the array.
Application #2 – Tiering – Improving Performance at the Pool Level
SSDs help storage arrays in storage tiering by dynamically moving data between different disks and RAID levels in meeting different space, performance and cost requirements. Tiering enables storage to pool (RAID group) across different speeds of storage drives (SSD, FC, SATA) and then uses analysis to put frequently accessed data on the SSD, less frequently on FC, and least frequently on SATA. The array is constantly analyzing usage, and adjusts how much data is on each tier. SSD arrays are used in applications that demand increased performance with high I/O. It is often the top tier in an automated storage tiering approach. Tiering is now available in most arrays because of SSD.
Application #3 – Fast Storage for High I/O Applications
Since arrays general treat SSD just like traditional HDD, if you have a specific high I/O performance need, you can use SSD to create a RAID group or Storage Pool. From an OS and application perspective, the operating system understands the RAID as just one large disk whereas since the I/O operations are spread out over multiple SSDs, thereby enhancing the overall speed of the read/write process. Without moving parts, SSDs contribute towards reduced access time, lowered operating temperature and enhanced I/O speed. It should be kept in mind that SSDs cannot handle huge data, and data for caching should be chosen selectiv; virtualizatioely based on what data will require faster access to – based on performance requirement, frequency of use and level of protection.
SSD Benefits in Virtualization
In a virtualization environment, there is the fundamental problem of high latency with host swapping primarily in traditional disks compared to memory. It takes only nanoseconds for data retrieval from memory whereas it takes milliseconds to fetch from a hard drive. When SSDs are used for swapping to host cache, performance impact of VM kernel swapping reduces considerably. When the hypervisor needs to swap memory pages to disk, it will swap to the .vswp files on the SSD drive. Using SSDs to host ESX swap files can eliminate network latency and help in optimizing VM performance.
The application of Solid-state Drives has become significant in achieving high storage I/O performance. Proper usage of SSDs in your storage environment can ensure your datacenter meets the demands of today’s challenging environments. If you are interested to learn more about the advantages of SSD over Hard Disk Drives (HDD), you can look at this comparative post from StorageReview.com.