SSD and HDD Hosting Overview
What is SSD and HDD?
Over the last few years, most of the major web hosting companies have transitioned their data center hardware from web servers installed with traditional Hard Disk Drives (HDDs) to new Solid State Drives (SSDs) for better performance and faster speeds. Some companies still offer web hosting plans based on HDD storage at a cheaper cost than SSD configurations, particularly on dedicated server and VPS accounts. On shared hosting plans, it is not always clear whether a company offers HDD or SSD storage on their hardware, although most webhosts prominently advertise SSD storage capability when they have it installed on their platforms. Overall, it is important to know the performance differences between the two main storage standards and to evaluate competing web hosting plans with regards to the cost basis per GB of storage capability provided under each format.
What is the Difference Between SSD and HDD?
Hard Disk Drive (HDD) storage technology dates back to the 1950s and operates similarly in many ways to phonograph recordings or vinyl records. Data is stored in patterns magnetically on a spinning wheel with each drive equipped with a sensor apparatus that will seek out the information and send it to the CPU. Data transfer speeds vary with the make or model of the equipment, RPM standards (5400/7200), the "disk-to-buffer" rate implemented , as well as according to the bus type which connects the HDD to the motherboard. The major bus types for HDDs include PATA, SATA , SCSI, SAS, and Fibre Channel. HDDs are also fundamentally similar to the "floppy disk" drives that predominated in the early era of computing, although they are now manufactured to support terabytes (TBs) of data storage.
In contrast, Solid State Drives (SSDs) became common around 2009 and contain no rotating parts in their design, constructed rather from NAND-Flash memory similar to what is used in RAM chips or thumb drives. SSDs offer much faster read/write times on data transfers compared to HDDs primarily because there is no head and arm mechanism used to seek out the information. SSDs use integrated circuits to store digital files in binaries instead of electromagnetic recording technology. In benchmark tests conducted on web servers, SSDs were shown to transfer 95% more data under heavy strain than HDDs and to perform on average at rates of 20x faster in processing I/O requests. SSD performance is also determined by the data transfer speeds permitted by the bus type, of which SAS, SATA, PCI Express, Fibre Channel, USB, & PATA are all frequently used in web hosting.
SSD VS. HDD – COMPARISON
When SSDs became common in the consumer market in 2009, they were initially priced quite expensively when compared to HDDs of equal storage capacity (measured in GBs or TBs). As most of the major web hosting companies had already invested heavily in their data center hardware, the introduction of SSDs in the marketplace initially proceeded on the model of premium upgrades or elite server provisioning. However, as the price of SSD technology has decreased and each web hosting company is forced to regularly upgrade their web server hardware every 2-3 years due to planned obsolescence or redundancy, SSDs have begun to replace HDDs across the board as a de facto standard common to every web hosting plan, primarily due to consumer demand, industry competition, and superior performance. The major advantage of using HDD storage in 2018 is that it is available much cheaper than comparable SSD equipment. Almost all of the cloud hosting found in the marketplace today is based on SSD standards, with only a small sector of the budget hosting industry offering cheap shared hosting plans still relying on HDDs exclusively. HDDs also have a significantly higher fail rate in production when compared to SSDs, although some companies can take advantage of the cost advantage of HDDs for data backups, offsite storage, and hosting large digital archives for downloads.
SSD Vs. HDD - Data Security
The major issue with data security and storage technology relates to the fail rate of the equipment, which can be caused by a large number of different variables on web servers used in production environments. Rackmount servers are not normally subject to the wear & tear of laptops or desktop equipment, however they function 24 hours a day at a much higher usage rates than consumer equipment. One of the main causes of server failure is overloading the hardware with I/O requests which the 20x faster processing ability of SSDs mitigates significantly. Another problem is that repeated use of the equipment under strain leads to mechanical failure. SSDs are viewed to be more reliable than HDDs because they lack the moving parts and spinning wheels that can malfunction, but they have another problem related to electron tunneling on the nano-scale that limits the number of times a specific sector of the chip can be recorded to that leads to bit errors or shorn writes.
In benchmark testing by third party experts, HDDs tended to fail on average at rates of 3.5% of the equipment over the life cycle of the drive, whereas SSDs failed at rates of around 0.5%. Web hosting data centers use RAID storage drives to mirror copies of client websites on different drives within the facility so that if one HDD or SSD fails, the data is preserved in another copy implicitly. RAID storage arrays are used on almost all shared hosting accounts and VPS plans, but are generally not included by default with dedicated servers. There are levels of data security related to RAID arrays and multiple storage drives that become expensive to implement for online businesses as they require more than one data center as well as offsite storage facilities. On most retail web hosting plans, it is the data center company that is responsible for these issues where only the users of private cloud, elastic cluster servers, and dedicated web server plans need to be particularly concerned about managing their own storage backups independently in case of major hardware failure or system crashes.
In benchmark testing by third party experts, HDDs tended to fail on average at rates of 3.5% of the equipment over the life cycle of the drive.
In benchmark testing by third party experts, SSDs tended to fail on average at rates of 0.5% of the equipment over the life cycle of the drive
SSD Vs. HDD - Hosting Speed
In the web hosting industry, the performance speed of SSD storage over HDD technology is so great that website owners are actually at a competitive disadvantage if they fail to sign up for a plan based on SSDs. In practical terms, however, this is most important for highly trafficked websites and mobile applications while the difference might not even be noticeable to small sites depending on the hardware configuration and user account density per machine. Web hosting companies also use a number of tactics to improve the performance of legacy HDD-based equipment and save money on provisioning. One of these is to run the MySQL database for websites from SSD hardware and serve the static files from HDD equipment. Another is to use reverse-proxy file caching and load balancing on network traffic with multiple copies of websites running in tandem on shared plans. This format allows user traffic to be routed to the hardware with the least amount of activity, generating better response times on legacy HDD-based web servers.
Other factors to consider with web storage performance speeds are the DNS server, the use of an integrated CDN service for file caching, and virtual RAM (vRAM) implementations. As the web hosting company normally manages the DNS server for clients, they can save money on bulk shared hosting plans by running the DNS requests through premium, SSD-based hardware for faster response times while hosting low traffic accounts on legacy HDD-based web servers. CDN services can improve the page load speeds of shared hosting account users who are stuck on HDD equipment and often included as a free bonus feature on these plans. Some web hosting companies offer premium upgrades to SSD hardware at a higher price while relegating their shared hosting customers to legacy HDD equipment with slower speeds. As many webhosts implement vRAM solutions on shared accounts that increase the amount of RAM available to CMS sites by running on a storage partition, it is particularly important to make sure that these plans include SSD hardware or the CMS response times will be noticeably slow. Similarly, many hosting companies offer "Cloud" VPS plans with SSD hardware options at a slightly higher cost than HDD-based options with much better performance rates.
HDD read speeds average about 128 MB/s and write speeds of 120 MB/s. In this category HDD is at a clear disadvantage compared with SSD equipment.
This a category is where SSD shines with average read and write times of over 500 MB/s and bursts of up to 700 MB/s.
SSD Vs. HDD - Power Consumption
According to the Institute of Electrical and Electronics Engineers (IEEE), data storage is responsible for 25% to 35% of the total power consumption used by web servers in operations. The total cost of electricity used by data centers internationally in 2016 was estimated to be at around $20 billion USD. Because of this, the lower power consumption required by SSDs in operations can save money over time for web hosting companies and private cloud owners, as well as reducing the environmental strain generated by the sector. In benchmark testing, an average solid state drive (SSD) requires 0.38 watts of power per hour while idle, 0.68 watts per hour to perform a read operation, 2 watts per hour in processing database functions, and 3.01 watts per hour at max write speeds. In comparison, a normal hard disk drive (HDD) consumed around 15x more power while idle and 2.5-7x more power in heavy operations than the SSD equipment. According to studies conducted by Rackspace and other companies, the energy savings of SSD hardware over HDDs is not enough to cover the price difference in purchasing the technology over the course of a 3-5 year term, but it can save some money for the major cloud operators in electricity billing as well as requiring less artificial cooling for a data center.
A normal hard disk drive (HDD) consumed around 15x more power while idle and 2.5-7x more power in heavy operations than the SSD equipment.
In benchmark testing, an average solid state drive (SSD) required significantly less power while idle and while performing tasks.
SSD Vs. HDD - Durability and Reliability
As noted above, SSDs have benchmarked at failure rates of around 0.5% over 3-5 years of use, compared to HDDs which fail due to mechanical issues at a rate of around 3.5% over the same period of time. Breaking it down more specifically, HDDs tend to fail at different rates depending on the year of implementation. For example, Backblaze reported 5.1% failure rates in the first year of data center use, 1.4% in the second year, and 11.8% in the third year. This is logical as firmware and manufacturing issues follow the initial installation of a hard drive and repeated use in web hosting under strain leads to mechanical failure after longer periods of time. Fail rates will also vary significantly based on the hardware manufacturer, the RPM speed, and bus type used with the drive on a web server.
In contrast, SSDs fail primarily due to being overwritten with data too many times on the same block. Most companies include a wear-leveling algorithm in the SSD firmware that is designed to mitigate the strain on NAND-Flash circuits under high-performance requirements. Some web hosting companies have been able to increase performance, save costs, and reduce the time on web server hardware upgrade cycles by replacing HDDs in existing equipment with SSDs. Unfortunately, SSD technology is too new in data centers for entirely accurate information on product longevity to be determined, but SSDs are expected to last longer in production use than the 5-6 year maximum lifespan of HDDs under similar situations. Most estimates suggest a range of 10 to 20 years for SSD storage hardware longevity, although many webhosts upgrade more frequently to take advantage of new technology standards.
Due its many moving parts HDD's fail at rates of around 3.5%, much higher than SSD's.
SSDs have benchmarked at failure rates of around 0.5% over 3-5 years of use.
SSD Vs. HDD - Cost
The biggest problem for web hosting companies holding back the industry-wide implementation of SSD technology over the last 9 years has been the higher cost per unit of storage. IT analysts estimate that the price per GB of memory space is 4x higher for SSD hardware over equivalent HDD options. For high performance users willing to pay a premium for elite web server configurations, the extra cost is justified by the 20x faster I/O and read/write speeds needed to support complex web & mobile applications at scale in production. However, for bargain rate or budget webhosts operating on a small margin with shared hosting plans, it has been a long process in completing the industry-wide change over to SSD technology. Primarily it has been user demand and business standards competition that has led the turn-over, although even in 2018 not every shared hosting plan is run on SSD-based hardware.
Because shared hosting companies also generally offer "unlimited" storage space on their plans, it is even more difficult for them to manage the costs of SSD investment in operations. VPS and dedicated server users are accustomed to paying a premium for SSD upgrades over HDD options on the same hardware specifications. Since Google changed their search engine algorithms to focus on page load speed over other factors, it has become even more important for business website owners , ecommerce sites, and web publishers to run their sites on SSD hardware for competitive advantage. Nevertheless, it is only recently that budget web hosting companies in the $3 to $7 per month range have begun offering SSD storage on their plans, and even now, not all of them do so. It is important to shop around and read the fine print on web hosting plans in order to make sure that a shared account has SSD-enabled hardware, and to avoid getting locked in to HDD options on a long term VPS or dedicated server plan.
Price per GB of memory space is 4x Lower than SSD hardware
Price per GB of memory space is 4x higher than HDD hardware
The introduction of SSD technology into the web hosting industry around 2009 has been a major game changing development, enabling much faster database processing and web page performance speeds, but hindered largely by the cost of investment and the routine 3-5 year cycle of hardware upgrades. In 2018, it would not be recommended for any high performance website or mobile app publisher to host their code on legacy HDD-driven hardware. The majority of shared hosting plans found on Linux & Windows platforms now include SSD storage support at affordable prices, although some companies keep charging an extra cost for the upgrade. VPS and dedicated server users can secure a discount on hardware if they choose to go with legacy HDD storage configurations, but with 20x slower speeds on I/O & read/write processes on average, there is little advantage other than the cost savings to do so. CMS users will especially appreciate the increased performance speeds if upgrading to SSD-driven servers from a HDD plan.
Should I Migrate to SSD Servers?
On shared hosting plans, most users receive an allocation of between 512 MB and 1084 MB of RAM with unlimited bandwidth and storage for the domain names. Some web hosting companies configure their servers to include extra vRAM allocations that run from the disk storage partition. In general, any website owner on shared hosting should determine whether or not their site is running on SSD hardware and migrate to another company at a similar cost range if the plan is still operating on HDD-based servers. vRAM options are not well suited for running on HDD when managing CMS code for web publishing, but perform almost equivalently to system RAM when running on SSD storage partitions. Usually it is worth the minimal extra cost for the speed gains to upgrade any PHP/MySQL website to SSD hardware, but budget users can implement free page caching and CDN solutions with their sites to gain near equivalent performance if locked into a legacy HDD platform.
As the cost has come down on SSD storage options for VPS and dedicated server plans, it makes little sense to run websites and mobile apps on hardware that will perform at 20x slower speeds than competitors. However, there is not any standardization of pricing in the industry for equivalent services, so it is necessary to shop around between webhosts to find the same hardware and software services at the lowest price. This is especially true if running on a managed CentOS platform with cPanel. Almost all of the cloud hosting plans offered currently in the marketplace are built around SSD-driven web servers with powerful multi-core processors. Many of the cloud hosting platforms include VPS-level provisioning that make for a cost-effective upgrade for CMS publishers running WordPress, Drupal, Joomla, Magento, etc. Another factor that makes a major difference with page load speeds on SSD/HDD hardware is low account density, where web hosting companies guarantee a lower level of shared domains registered per server. Choosing a web hosting company with free website migration services makes the transition to a SSD host extremely easy for small business owners and web publishers.
Or Should I Keep my HDD Server?
Many of the budget web hosting companies have developed unique solutions for making their legacy HDD hardware run at competitive speeds on shared hosting plans, such as using load balancing on network traffic with multiple copies of client websites running in parallel. Websites primarily composed of static HTML pages that do not draw heavily on server resources may not notice a major difference between HDD and SSD plans. Some companies with large file archives and download services that do not require the fastest speeds may be able to save money on storage by choosing HDD options with VPS , cloud, or dedicated server plans. Similarly, single user blog sites with less than 1000 to 2000 page hits per day can make extensive use of free page caching and CDN utilities to remain on budget hosting with unlimited HDD storage at costs as low as $3 per month. It may not be worth the time and effort to migrate to another host if a published website or multi-domain portfolio is performing adequately under low traffic requirements with a long term discount contract on a shared hosting plan.
Migrating to SSD
In order to migrate to a SSD hosting plan, there are two basic options: do-it-yourself or have the web hosting company staff do it for you. It largely depends on the specifics of the website or multi-domain portfolio as to which is better. Some companies offer a free website migration service to bring in new customers. For example, if you are on a shared hosting plan, but determined that the platform is not running on SSD hardware, search for another host with equivalent services and see if they offer a free migration option. Often you will need to give your account login details to the data center staff for them to access cPanel or FTP and pull the database plus site files to the new server. Some companies charge as much as $180 for this service so it pays to shop around and find a free migration offer. However, many projects are too complex for unknown staff to manage or some businesses will not want to share their login information with strangers, requiring either the DIY approach or hiring a paid expert to do the work.
In terms of manual transfers, the basic process is to pack the website files into a zip file for download and to export the database either through phpMyAdmin or the CMS. Some users may choose to install a new copy of the CMS on the SSD host and then just export the database to create a mirror of the website. It largely depends on the CMS, third-party modules/plugins, custom themes/templates, and the number of saved images embedded in the web pages that need to be copied or cloned. Another method is to use FXP and transfer all of the files between the two hosts without a download to the desktop. Experienced users may also be able to use command line tools to expedite the procedure. With cPanel, all of this can be done using the File Manager utility for zip archives and phpMyAdmin for database exports/imports. With WordPress, Drupal, Joomla, and other CMS scripts, there are a number of third-party modules and extensions that can help with the process. The main requirement is to create a new MySQL database, user, & password, then update the CMS script with the credentials (i.e. wp-admin/admin.php for WordPress or the settings.php file in Drupal) after the original codebase has been transferred.