Personal computing discussed
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bfg-9000 wrote:It's not just failures--have you ever tried to use an undelete utility on a SSD? Garbage collection seems to be so aggressive that in many cases you only have about ten minutes to use it before it gets zeroed out.
just brew it! wrote:bfg-9000 wrote:It's not just failures--have you ever tried to use an undelete utility on a SSD? Garbage collection seems to be so aggressive that in many cases you only have about ten minutes to use it before it gets zeroed out.
With TRIM I am surprised you even have 10 minutes. I'd expect it to be less, since the OS is explicitly telling the drive "please forget about the content of these flash blocks so we can re-use them without forcing you to do a read-modify-write".
Noldor wrote:So, the typical undelete utilities one can use on a HDD don't work on SSDs?
Noldor wrote:just brew it! wrote:bfg-9000 wrote:It's not just failures--have you ever tried to use an undelete utility on a SSD? Garbage collection seems to be so aggressive that in many cases you only have about ten minutes to use it before it gets zeroed out.
With TRIM I am surprised you even have 10 minutes. I'd expect it to be less, since the OS is explicitly telling the drive "please forget about the content of these flash blocks so we can re-use them without forcing you to do a read-modify-write".
So, the typical undelete utilities one can use on a HDD don't work on SSDs?
Waco wrote:Noldor wrote:So, the typical undelete utilities one can use on a HDD don't work on SSDs?
If you have TRIM enabled, no.
If you don't have TRIM enabled, they're basically the same. Both SSDs and HDDs retain the data you wrote until you overwrite the same LBA or secure erase them. Garbage collection on an SSD will *never* touch blocks that haven't been overwritten.
Waco wrote:I run my 8-way RAID 0 without TRIM and don't miss it a bit.
CScottG wrote:Waco wrote:I run my 8-way RAID 0 without TRIM and don't miss it a bit.
Not often you hear about using SSD's without TRIM these days. I setup my father's system without TRIM - because I had to (given that he's only using SSD's now, and in relation to the OS). UnRAID doesn't have TRIM pass-through for main (array) drives (..though it does for caching drives), and that's what I chose for his system. Still, the drive space is largely limited in the amount of capacity that is being used with it - from the virtual machines he uses (1 Linux and 1 unregistered Win 10 at the same time.) I've got copies of each - so 4 virtual machines in total, but each machine doesn't have much space allotted to it and UnRAID doesn't seem to be greedily hogging drive space on the array as time goes by (..though it does like to go through memory!),