In hosting there are multiple storage options available. However the two available major options are SATA and SSD. SSD storage is growing faster and replacing traditional SATA in server and desktops as well. So cloud is not exception for this. SSD is much faster and expensive than SATA storage. So many of us get confused while deciding storage option – Disk Throughput. Therefore our business cloud. The below points will help you decide a better storage option for your cloud.

What is the use of Storage?

Storage is used to store data, which can be accessed later. When you upload a website on the server, it gets stored on the underlying storage. And when anybody accesses your website, the web server serves it from the same storage.
Storage has two major tasks “read” and “write”. Speed of read-write from-to storage mainly depends on the type of drive we have used. “Read-write” speed of drive is also called as “Drive Throughput”, which is generally in MegaByte per second (MB/s). The faster the read-write drive, the faster your content.

There are 2 major storage options availabe in the market: SATA or aka HardDisk Drives (HDD) and Solid State Drives (SSD).

What is SATA HDD?

SATA HDD is nothing but a traditional disk drive used for storage. In simple sense it has two major mechanical components: rotating disks aka platters and magnetic head on moving arm. Head read-write data is on rotating platters.

What is SSD?

SSD is next generation drives. It does not have any mechanical components. SSD uses NAND-based flash memory to store data. That is why SSD can read-write data much faster.

Now we should understand the major differences between SATA or aka HardDisk Drives (HDD) and SSD:

Architecture            

SSD

Non mechanical design – NAND flash mounted on circuit boards, and are shock resistant.

SATA (HDD)

Mechanical design – consists of various moving parts making them susceptible to shock anddamage.

Speed

SSD

SSDs are much faster than SATA. All part of SSD can be accessed at one time. Average throughput by consumer grade SSD is around 600MB/s  and enterprise grade SSD is in multi-gigabyte/s. Please note that throughput depends on port and disk type.

SATA (HDD)

It can only access data faster which is closer to the read-write head. The maximum throughput by enterprise grade SATA drive is 140MB/s. Practical throughput we get around 70 to 10 MB/s. Please note that throughput depends upon port, disk rotating speed (RPM) and disk type.

Read Latency time

SSD

Low. Because the data can be read directly from any location.

SATA (HDD)

Much higher than SSDs. Read time is different for every different seek, since the location of the data on the disk and the location of the read-head make a difference.

Capacity

SSD

SSDs have no moving parts to fail mechanically. Each block of a flash-based SSD can only be erased (and therefore written) a limited number of times before it fails. The controllers manage this limitation so that drives can last for many years under normal use.

SATA (HDD)

HDDs have moving parts, and are subject to potential mechanical failures from the resulting wear and tear. The storage medium itself (magnetic platter) does not essentially degrade from read and write operations.

Reliability

SSD

SSDs were available in sizes up to 2 TB, but less costly 128 to 512 GB drives were more common.

SATA (HDD)

HDDs of up to 8 TB were available.

Susceptibility to environmental factors

SSD

No effects on shocks and vibrations. Also less vulnerable to weather changes such as humidity, salty air (near coastal line).

SATA (HDD)

HDDs have high speed rotating platters and floating head which makes them susceptible to shock and vibration. Can damage due to trpm –query –list libcgroup | lesshis weather changes.

Cost / GB

SSD

-Disk Throughput: Consumer grade SSD costs around Rs. 50 to 60 per GB. Enterprise grade SSDs are much expensive than this.

SATA (HDD)

Enterprise grade SATA HDD costs around  Rs. 5 to 6 per GB.

Choosing Appropriate Storage Option for your workload

Though SSD gives higher throughput or performance, it is more expensive than SATA Drive. So while choosing, storage needs to work on below points to find appropriate storage for your hosting. This will help serve the purpose and will be cost effective.

– Disk Throughput:

This is a very crucial point in deciding the storage type. As mentioned earlier drive throughput is simply read-write speed of drive. It states that higher throughput faster serving, as well as saving content on it. However, we may not require that kind of speed in many circumstances. For eg. If we have just a static website or websites with light graphics and simple structure, then SATA drive can be sufficient to serve the website. But at same time if we are planning to host many websites on one underlying storage then we may need a higher throughput to serve the content faster.

Simple calculations:

If size of webpage is 5MB and there are 100 clients per second who load this webpage and there is no caching set. Then theoretically 5 x 100 = 500MB read/second will occur. In this scenario you will need a drive which can provide required read/secs throughput i.e. SSD. Now there are other components which may affect the performance for eg. Caching, Internet Bandwidth, CDN, etc. But that is not in the scope of this article. If caching is set then there will be lesser read/secs required. Please note that in above example you will also need a network bandwidth which can support 500 MB/sec. Otherwise SSD is of no use.

Required Size of Storage

This is key for deciding storage. What is the size we are looking for. If we need a huge size requirement such as 500 GB or 1 TB then pricing will come into picture.

Conclusion: If you just want to store more data and you are not very concerned about website speed or not many clients per second then you can go with SATA HDD storage.
And if you want lightening speed for a number of clients/secs and performance oriented than just dumping data then you can go with SSD storage.

-Written by Neelesh Gurjar, Senior System Admin, QualiSpace