It was designed for disks yet has been shown to be effective on SSD. Not all algorithms grow better with age.
Cheers, -- Cirt talk According to the formula in the article itself, that would mean that the drive stores only half of the bytes given to it by the operation system.
In other worse, according to the formula in the article, the drive is losing half the information which clearly is not a good feature. The claim is deceptive if it is done by using compression since compression is a concept that is orthogonal write amplification index write amplification and should not be counted when calculating write amplification.
Wikipedia should not be a commercial for SandForce and if we are going to talk about write amplification levels below 1. By the definition of write amplification in the article, the claim makes no sense other than as a claim that a drive is losing information.
OK, so the first reference does talk about a 0. The direct link is http: However, that page merely documents that SandForce claims to have a 0. The speculation is indeed that there must be compression going on.
Since there is no linked hard information about what the claimed 0. Both Intel and SandForce make claims about write amplification. Are you saying one is more relevant than the other?
I see in your follow up edit you realized the source referenced had more than one page and you now understand how a drive can write amplification index a write amplification below 1 and you no longer feel it is deceptive. Since many online articles will appear on multiple URLs, there is no requirement to explicitly state what page of an article the reference is made unless it is a particularly large article.
Your follow on comment says the source speculates as to how SandForce might be achieving the reduced write amplification. I agree it is.
The paragraph you are referencing in the article is citing what product claims companies are making. SSDs with flash memory must do everything possible to reduce the number of times they write and rewrite data to the SSD. During garbage collection and wear leveling the SSD will write data more times than the host requested.
This gives rise to the "amplification" of those writes. An SSD that can do things to reduce the number of time it writes data to the flash or how much data it writes to the flash would be better because it will enable the flash to "last longer" and if it is writing less to the drive initially then it gets done writing data sooner than other drives.
That would give that SSD a faster write time than any other drive. Last time I checked third party reviews of the SandForce drives were showing actual performance tests which are much higher than many other drives.
Since this article is all about write amplification I think any information related to that subject is likely relevant. Untilit was assumed that write amplification could not drop below one, but that year SandForce made the claim they had a write amplification of 0.
I should have simply deleted this, but I already wrote the edit summary for the article edit -- Tomdo08 talk Your additions appear to violate the WP: Your modification to the Product statements section appear to be your opinion without any source reference and are appear to me as being worded in a controversial and non-encyclopedic manner.
You said there had already been some discussion about this in the section you mentioned above, but I only see one unregistered user made some opinionated statements as well. That would not constitute a discussion.
You may not realize, but this article already passed the review criteria for WP: GA which required it be free of any WP: Certainly there is always room for improvement and it is very possible someone missed something in that review.
I would be happy to discuss how you and other editors think we should update the article if there is any debate about the truth of the content in the current article as it is worded now.
Note that I did not revert your other edits to the article which did not violate the rules I mentioned above. As I understand it, most file systems will reuse deleted blocks first in order to avoid fragmentation, and therefore the SSD will gain benefit from free user capacity even if there is no TRIM.
OR -- sciencewatcher talk Over-provisioning on an SSD. What is referred to as "Over-provisioning Level 1" is better known as "rounding".
What is referred to as "Over-provisioning Level 3" is rather messy. This is not over-provisioning per se, but instead the OS is telling the controller that space is unused and need not be preserved thus reducing write-amplification.
A result similar to what over-provisioning achieves, but not actual over-provisioning.
Lastly, declaring smaller partitions may have worked with the older MBR partitioning, with GPT the backup GPT must be written at the end of the medium, which will prevent a controller from grabbing that space for additional over-provisioning.
The level three is simply not using all the space on an SSD, on the logical level, so the controller has more never-to-be-used space to play with.The paper starts with an explanation of write amplification, read amplification, and space amplification, the metrics that will be used to compare B trees, FT indexes, and LSMs.
These are nicely detailed sections and well worth the price of admission.
Since each index AM has its own view of the index tuples, each AM must implement its "amrecheck" routine. This routine to used to confirm that a tuple returned from a WARM chain indeed satisfies the index keys.
If the index AM does not implement "amrecheck" routine, WARM update is disabled on a table which uses such an index. ***Under best write amplification index (WAI) with highest sequential write value. May vary by density, test configuration, workload and applications.
Related Technology. Functional/Reliability Testing. MyRocks advantages over InnoDB. Jump to bottom. Index entries are sorted in RocksDB (like many other databases). When using multi-column indexes, very often first N bytes are the identical to previous index entry. Write Amplification is much smaller than InnoDB.
On pure flash, reducing write volume (write amplification) is important. Become a SSD expert in minutes! Ryan Smith [email protected] Maximizes the lifespan with low Write Amplification Index (WAI) Robust Data Protection.
Software/hardware write protect option. Multiple user data security zones.
Software/hardware secure erase function. PowerShield and DataPhoenix technologies prevent data .