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Samsung 
Solid State Drive

White Paper

©

 2013 Samsung Electronics Co.

Summary of Contents for 840 EVO

Page 1: ...Samsung Solid State Drive White Paper 2013 Samsung Electronics Co ...

Page 2: ...will benefit from a more clear understanding if you review all of the content in this booklet in the order in which it is presented In addition to explaining why SSDs are a worthwhile upgrade from their traditional mechanical counterparts you will find an introduction to NAND technology the fundamental building block of SSDs a discussion of various SSD specific technologies an overview of how to u...

Page 3: ...ditional Hard Disk Drive HDD counterparts is because of their incredibly fast data access times the delay between the request and completion of a read or write operation A modern SSD boasts random data access times of 0 1ms or less whereas mainstream 2 5 consumer HDDs take about 10 12msormore Asyoucanseeinthebelowcomparisontable SSDsareover100timesfasterthanHDDsinaccessingdata including data seek ...

Page 4: ...d random performance capabilities of an SSD Fast sequential speeds allow for quick file copies and smoother performance when working with large files like videos However it is random performance measured in Input Output Operations Per Second IOPS that is perhaps the most important performance metric for SSDs A large portion of storage activity is made up of 4K random writes a metric that measures ...

Page 5: ...fers and components for use in SSD products which require the utmost quality in order to safeguard precious user data In fact Samsung s quality assurance procedures have been acknowledged by OEM customers worldwide each of which must run their own qualification processes before implementing a drive into consumer products Efficiency Imagine if the only way you could get anything done was if you wer...

Page 6: ... This revision also introduces Native Command Queuing NCQ a feature that improves multitasking performance SATA 2 0 is more than capable of handling the best hard drives on the market but it is easily overwhelmed by the onslaught of Flash devices SSDs that are now popular Computers purchased in 2005 or later are likely equipped with SATA 2 0 support SATA 3 0 Released in 2009 SATA 3 0 also known as...

Page 7: ...um performance on all SATA interfaces current and legacy An 840 Series SSD will outperform both an 830 Series SATA 6Gb s and a 470 Series SATA 3Gb s SSD connected to the same SATA 3Gb s port as shown in the table below In fact an 840 Series SSD will outperform any SATA 3Gb s SSD on the market on the same system setup An investment in an 840 Series SSD is therefore future proof in that an upgrade n...

Page 8: ...riate key to enter the BIOS this is usually DELETE F2 or F10 Find the section for Integrated Peripherals or Storage configuration Change Configure SATA as or PCH SATA Control Mode to AHCI Consult your PC s user manual for instructions for your specific machine Ideally AHCI mode should be enabled via the BIOS BEFORE installing the Operating System OS On newer systems this is generally the case If i...

Page 9: ...er down This is convenient for multi drive systems where an SSD is in use as a secondary drive Rather than having to quit all running programs and shut down the computer a new secondary SSD can be inserted to complement or replace an existing drive without adding unnecessary steps to the workflow What if my system doesn t support AHCI If you have a system that does not support AHCI or if you fail ...

Page 10: ...mand in RAID 0 arrays In the past the lack of TRIM for RAID 0 was a source of frustration as the performance improvements initially gained through the RAID array were mitigated by the performance deficits caused by the lack of TRIM Thus with the addition of TRIM support for RAID 0 it is useful to understand RAID technology and who and why an individual might choose to use it RAID Levels RAID 0 RAI...

Page 11: ... enjoy the performance advantages that RAID 0 provides Because it lacks redundancy however RAID 0 is not suited for mission critical tasks and should be supplemented by a robust backup system RAID 1 which writes all data identically to two or more drives is ideal for mission critical workloads such as small servers that cannot experience significant downtime The speed is the same as it would be wi...

Page 12: ... structure of the cell over time Thus each cell has a finite lifetime measured in terms of Program Erase P E cycles and affected by both process geometry manufacturing technique and the number of bits stored in each cell The complexity of NAND storage necessitates some extra management processes including bad block management wear leveling garbage collection GC and Error Correcting Code ECC all of...

Page 13: ...weenonestateoranother Compoundingmatters is the fact that the oxide layer gets smaller with each advance in process geometry as we shrink the size of the cell the oxide becomesthinner Athinneroxidelayerwillwearoutfaster meaningthecellwillhavealowerlifespan MLC NAND Today Manufacturers have made massive strides in managing the limitations of NAND technology Sophisticated bin sorting algorithms allo...

Page 14: ...mory technology Today s NAND based storage will still far outlive the useful lifespan of the devices it powers Choosing to sacrifice a bit of excess lifetime and performance in favor of dramatic cost benefits will allow manufacturers to deliver NAND technologyanditsmanyadvantagesovertraditionalstoragetechnologytoafarwideraudience Samsung has taken the first step by introducing 3 bit MLC NAND to th...

Page 15: ... generations of Toggle DDR and ONFI NAND are distinguished by how fast the strobe or clock in the case of Synchronous ONFI NAND itself runs how fast it can complete one cycle Toggle NAND vs ONFI NAND In the NAND flash industry there is some variation in implementation depending on manufacturer Samsung and Toshiba make Toggle NAND whereas everyone else makes what is called ONFI NAND Each generation...

Page 16: ...f real world impact In practice the use of synchronous versus asynchronous NAND has no impact on SSD performance What actually affects performance is the generation of the NAND e g SDR ONFI 1 0 Toggle 1 0 ONFI 2 0 etc When discussing NAND type therefore it is inaccurate to refer to it simply as either synchronous or asynchronous when referring to performance Why Samsung As the 1 player in the worl...

Page 17: ...mind let s look at what would happen if we wanted to re use a page that contained old data If the SSD wanted to reuse an existing no longer valid page the other valid pages in the block would have to be copied into an empty NAND cell while the entire block was erased The SSD would then rewrite the entire set of valid data old and new to the intended cell This process is complex and time consuming ...

Page 18: ...the drive may not have a chance to sit idle and prepare free blocks Samsung s SSDs are always prepared for what s next The chart below shows what happens to performance when an SSD is hammered with a non stop data flow for 6 hours The 840 and 840 PRO Series SSDs level out at a significantly higher performance level and the 840 PRO is able to hold on to its peak performance longer than many other d...

Page 19: ...n the process technology e g 27nm 21nm 19 nm etc and on the program mechanism e g SLC MLC In order to overcome this limitation the SSD firmware employs a wear leveling algorithm that guarantees that write operations are spread evenly among all NAND cells Using this technique no single cell should be unduly stressed and prematurely fail If too many cells were to fail the entire block would have to ...

Page 20: ...um amount of OP is not user configurable and will vary from vendor to vendor There is no right amount of OP to set aside and it is best to vary it by capacity and situation If you don t want to use Magician s recommendation or if you are a professional or more advanced user with different requirements you are free to set aside your own OP space To decide how much to set aside you must consider you...

Page 21: ... hand reduce repeating steps like getting the salt from the pantry and putting it back away and increase your working speed The same goes for SSDs Give them more room to work and they can do it more quickly and efficiently reducing WAF and increasing performance at the same time OP and the 840 Series SSD As NAND process technology advances the chips themselves become increasingly smaller As they s...

Page 22: ...dule TPM standardized by the Trusted Computing Group in conjunction with FDE the integrity of the boot environment can also be verified SED Self Encrypting Drive SED is a term that refers to a storage device that implements hardware based FDE Therefore an SED is a special case of FDE SEDs boast better performance security and manageability compared to software based FDE implementations which commo...

Page 23: ...d control over authentication With third party software support IT managers can set detailed security provisions to restrict access by partition physical location of the laptop etc Anyone interested in this level of security management should research enterprise class TCG OPAL SED options Someone who wants to manage a personal machine or an SMB that depends on its employees to handle most of their...

Page 24: ...ithin the manufacturer s declared specifications So for example rather than complete data loss the drive may simply begin to run slower As with any technology the SMART status is not infallible and may not necessarily indicate past or present reliability The SMART sensors may malfunction for instance or a serious mechanical failure may destroy access to the SMART status Finally it is important to ...

Page 25: ...al count of the number of failed erase requests ID 183 Runtime Bad Count total Equal to the sum of the Program Fail count attribute 181 the Program Erase Fail count attribute 182 and the Read Fail count This summary value represents the total count of all read program erase failures ID 183 Uncorrectable Error Count The total number of errors that could not be recovered using ECC ID 190 Air Flow te...

Page 26: ...ession algorithm will be able to shrink the amount of data it must actually write to the NAND flash Samsung SSDs perform equally well with Repeating and Non Repeating data because the Samsung MDX controller does not use compression Thus when there is a large discrepancy between competing drives it is a good idea to check whether or not the benchmarking utility was sending Random or Non Random data...

Page 27: ...sses RAM etc IOPS numbers are directly affected by the NAND components storage controller and NAND interface speeds which may all influence random data seek time For the vast majority of users the most meaningful Iometer scores will be those of 4K random Read and Write performance at a Queue Depth of 1 32 The example screenshot above shows Random Write performance for the 840 PRO SSD Trace Based B...

Page 28: ...tstanding pending number of IO requests that must be handled by the drive Multiple requests are placed in a queue of a specific length where they will wait for their turn to be addressed by the SSD if another task is already underway The most common queue depths to test are a Queue Depth of 1 which is typical of light consumer workloads and a Queue Depth of 32 which is representative of a heavy wo...

Page 29: ...es on a regular basis Many manufacturers like to brag about peak performance and Samsung could have designed its SSD to have a similar performance profile Instead it chose to focus on real world users as its baseline rather than topping a particular benchmark That s not to say the 840 Series won t top the charts it will it just wasn t the design focus The best picture of a Samsung SSD s performanc...

Page 30: ...ng In fact customers may notice that Samsung releases very few firmware updates This is a testament to the quality of the original testing procedures and the superiority of the firmware code fewer problems to fix is a good thing In the rare case that Samsung does issue a firmware update SSD Magician makes it easy to upgrade your SSD Magician will notify you of any available updates and most update...

Page 31: ... manufacturers who each have different manufacturing processes while Samsung s proprietary SSD controller is engineered solely to work with its own NAND which means engineers can focus all of their efforts towards one common specification As the most integrated SSD manufacturer in the industry Samsung controls all of the most crucial design elements of an SSD NAND Controller DRAM and Firmware Work...

Page 32: ...ns SSDs The regular quality chips can be used for less demanding applications like USB storage devices that do not experience consistent heavy use The Most Experience Samsung has been a number one player in the semiconductor industry for over 20 years For 6 of those years it has been the largest supplier of SSDs to the preinstalled PC business Designing a storage device like an SSD is no trivial t...

Page 33: ...s qualification and reliability testing procedures and an advanced global support network the 840 Pro is a welcome addition to any power user or professional workflow Samsung Magician has been enhanced for advanced users as well with the addition of superior easy to use disk diagnostic and management features with a simple graphical drive health indicator Trust Samsung Samsung has a long track rec...

Page 34: ...ge and experience across every major SSD component and Samsung s expertise is embodied by its Average Failure Rate AFR which is among the industry s lowest at 0 05 Thus businesses that choose Samsung SSDs benefit from reduced down time and repair costs fewer data loss incidents and increased productivity since fewer employees must deal with inconvenient hardware repairs Unrivaled Performance with ...

Page 35: ...Samsung has a long track record of excellence in the memory industry With new business friendly features redesigned disk management software and next generation performance capable of extending the life of aging hardware Samsung s 840 and 840 Pro Series SSDs represent a solid investment for any business looking to maximize the effectiveness of its IT resources ...

Page 36: ...theuser automaticallymovingthecrucial SystemPartition to theSSDandleavingtheuserfreetoconcentrateonthepartitionsthatcontaintheiroperatingsystem programs anddata Recommendation and User Options Next SDM will recommend a plan of action and allow the user to customize how the migration will proceed The first partition which generally contains the Windows operating system installation is added automat...

Page 37: ...stalled connect your new SSD to your PC either via SATA for desktop users or via the adapter cable for laptop users and launch the software As it loads SDM automatically scans the system for the presence of any connected storage devices so there may be a noticeable delay as the software gets ready Click Start to begin the disk scan and diagnosis step On the next screen click on up to one 1 additio...

Page 38: ...m Reliability along with detailed descriptions of each OS setting and why they are turned on or off for each profile This feature should reduce user confusion about OS configuration a common question among new SSD users and the Magician team is excited to outline what s changed Optimization Profiles Magician s new Optimization Profiles were chosen specifically to address the 3 most common types of...

Page 39: ...the system goes into hibernation the contents in DRAM are copied to NAND flash Because this produces extra writes and may require a significant amount of storage space to function this feature is turned OFF for Maximum Capacity and Maximum Reliabilty modes Laptop or Desktop users who frequently leave their machine for a period of time but demand a quick resume time may wish to enable this feature ...

Page 40: ...ty of the SSD and is thus enabled for all profiles Enabling Write Cache does however increase the risk of data loss if the system power fails or the drive is removed suddenly This is because DRAM is a volatile storage medium that loses its contents in the absence of power which means that data stored in the DRAM cache may not have a chance to be flushed saved to storage NAND in the event of sudden...

Page 41: ...configuration profiles Users should implement a secondary backup solution using an external storage device to protect themselves from unexpected system failure Alternatively users with multiple internal storage devices in their system can redirect the storage location of System Restore via the Windows System Restore Dialogue Box which is accessible via the Advanced tab in Magician Wrap Up The OS O...

Page 42: ...lopment Team Sungchul Kim Principal Engineer Jisoo Kim Senior Engineer Jong Tae Park Senior Engineer Pilsung Kang Senior Engineer Application Engineering Group JB JongBaek Chang Principal Engineer Jeff Kim Senior Engineer Flash Memory Planning Team Eric Hong seok Chang Senior Engineer Controller Development Team Myeongeun Hwang Principal Engineer Contributions ...

Page 43: ...www samsung com ssd ...

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