how to choose suitable SSD write durability TBW for pgrade or new computer? [closed]

I searched many reviews and descriptions about SSD specifications but couldn't find convincing information.

Write durability of the memory cells TBW seems to be the most important, but how to review its effect on usage when most normal users like me use the large capacity of the HDD/SSD to store data for a long time without change, so most of the SSD space will be written no more than few times.

The real problem is the System drive(s) which also contain(s) the swap area which will be written thousands of times for swap data and lots of times for considerable system and application files. Considering this I don't see a big difference between SSD brands and designs.

If we want 1 TB SSD and choices for TBW are 300/4500/600/750 means the more affected memory cells could be rewritten between 300-750 times both are less than expected rewrite for 1 year work.

But SSD were working for much more than that, so I expect that a SSD controller could detect the failing cells and reallocate the addresses to not affected banks, is that true? If that is the case then the total durability for the SSD will be very long, until the controller reallocation database became very large and stop functioning, of course the SSD speed will decline as the reallocation DB become larger, if such technique is really exist "it does not exist in RAM".

Solution 1:

1. Comments regarding your posting

Write durability of the memory cells TBW seems to be the most important, but how to review its effect on usage when most normal users like me use the large capacity of the HDD/SSD to store data for a long time without change, so most of the SSD space will be written no more than few times.

Your use profil is not hitting the boundaries of the SSDs. If you want to "review" you have to test the SSDs by reading and writing continuously until they break.

The real problem is the System drive(s) which also contain(s) the swap area which will be written thousands of times for swap data and lots of times for considerable system and application files. Considering this I don't see a big difference between SSD brands and designs.

This is a false conclusion. If you accept your conlusion asking the question becomes useless. The use of a SSD as a drive where the operating system and swap data resides makes a failure more likely.

If we want 1 TB SSD and choices for TBW are 300/4500/600/750 means the more affected memory cells could be rewritten between 300-750 times both are less than expected rewrite for 1 year work.

How do you get to the implicit conclusion above that you are writing 1 TB per day?

But SSD were working for much more than that, so I expect that a SSD controller could detect the failing cells and reallocate the addresses to not affected banks, is that true?

The controller does not want to detect failing cells. He does everything to distribute wear evenly by internally reassigning cells.

If that is the case then the total durability for the SSD will be very long, until the controller reallocation database became very large and stop functioning, of course the SSD speed will decline as the reallocation DB become larger

There is no need for a database. There is just one table needed which assigns LBA sector numbers to flash cells and location therein. Furthermore a table containing a write counter is necessary for flash cells or group of flash cells. Both table do not grow in size when being realized as an array.

, if such technique is really exist "it does not exist in RAM".

That does not matter.

2. Recommendations

Your SSD selection is determined by your preferences which are unknown for us.

Here are some issues you can think about:

1. Can I afford the loss of SSD data? I only use SSD as a system drive. I can recover my private system the long way using installation media and a collection of software (no business continuity issue) or the fast way by using a complete system backup which I have but would have to be updated.

=> I can afford the loss of SSD data.

2. Price per Terabyte written

The following lines assume that most private computer users rarely make a backup - like me.

3. Readibility of the state of wear? I compared SMART parameters of SSDs from Adata, Crucial and Western Digital. Although they share some common attributes, each manufacturer uses parameters that the other do not use.

4. Your use strategy: a) Not writing the full TBW storage figures creating additional breakdown security b) Exceeding the TBW hoping to exploit a safety margin from the manufacturer

5. Test have shown that overusing a SSD result in different types of breakdowns. Some SSDs remain still readible, other fail completely. Would you pay higher prices for products that only convert to read-only?

6. Assuming that you are faced with a breakdown you can research for which flash controllers the data recovery scene has already complete time-saving rescue solutions.