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post #8 of (permalink) Old 08-28-2019, 09:16 AM
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Quote: Originally Posted by briank View Post
That's interesting that the "system area" which may also be known as the FTL (Flash Translation Layer) has a fixed area of flash on a "Pro" drive. I guess it must be a cost savings measure to save on DRAM where a true enterprise class SSD would keep its FTL and only write to the system NAND area on power down. This type of FTL implementation is probably typical in most modern low cost SSDs though.
Hmm, looks like it's still stored in DRAM (for performance reasons) but flushed more frequently to NAND due to lack of backup capacitors.


Due to the high cost of capacitors and the price sensitivity of the client SSD market, client SSDs do not normally include full power loss protection in the form of backup power circuitry. While the FTL is frequently flushed from the DRAM to the NAND, there is still a window of opportunity where the DRAM contains a newer version of the FTL in the event of an unexpected power loss. Fortunately, there are alternative and more cost efficient mechanisms to prevent the FTL from corrupting.

Quote: Originally Posted by briank View Post
I think this limitation of the drives could make the case that good system design is to buy a smaller ~256GB boot SSD and not use your expensive 2TB primary storage SSD as a boot/OS drive. That way you can keep the large drive for a long time and just plan on upgrading your OS drive every 4-5 years.
Unfortunately, using the same SSD for boot/OS and storage is sometimes unavoidable (e.g. laptops, NUCs). Although it's good that even ultra small form factor computers nowadays support M.2 + 2.5.
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