Overprovisioning?

haralds

macrumors 65816
Original poster
Jan 3, 2014
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Silicon Valley, CA
My last system SSD died after two years of heavy use.

Some reports indicate that overprovisioning has benefits. But it seems like as long as trim is enabled and the drive is left with a lot of free space the same impact is achieved.

I am using dual MX500 2TB for system and data formatted APFS. On Windows the Crucial Storage executive provides a special function to reserve space for OP.

I can see the need for OP designated space without trim.

No clear answer in articles I searched.
 

justinkr

macrumors member
Jan 20, 2017
52
4
Hmm~ never heard of it. And I never had that problem. I am currently running my Mac pro with Samsung SSD 500GB and 2 1tb hard driver were raided 0. Still run never had any issues. Knock on wood.
 

h9826790

macrumors G5
Apr 3, 2014
14,148
6,785
Hong Kong
Hmm~ never heard of it. And I never had that problem. I am currently running my Mac pro with Samsung SSD 500GB and 2 1tb hard driver were raided 0. Still run never had any issues. Knock on wood.
With TRIM ON, all free space are effectively serve as OP. So, no need to reserve more space for OP.
 
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AidenShaw

macrumors P6
Feb 8, 2003
18,628
4,628
The Peninsula
With TRIM ON, all free space are effectively serve as OP. So, no need to reserve more space for OP.
To be more precise - all space from files deleted when TRIM is active is effectively OP.

If the disk was ever run with TRIM disabled, free space may or may not be OP. Disk utility can scrub free space and make sure that it is TRIM'd and used as OP.
 
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deconstruct60

macrumors G3
Mar 10, 2009
8,897
1,752
My last system SSD died after two years of heavy use.

Some reports indicate that overprovisioning has benefits. But it seems like as long as trim is enabled and the drive is left with a lot of free space the same impact is achieved.
The latter is important. Cranking up the over provisioning means no end user level application can eat too far into the free space. ( Can easily do the same thing without a fancy tool by just partitioning the drive so that one parturition (e.g. 10%) was left unformatted or used. )

Some folks think that 10% is "a lot of free space" and run their drives done to single digits. It is not.


I am using dual MX500 2TB for system and data formatted APFS. On Windows the Crucial Storage executive provides a special function to reserve space for OP.
Mixing vastly different workloads onto a single disk can have impact also.


I can see the need for OP designated space without trim.
TRIM won't do much if have bulky stuff that sits and one place and the wear leveling doesn't spread it out over the aging cells over time. There so also be time for the SSD to do internal housekeeping. If constantly hammering the driver 24/7 or sending it to sleep whenever not in active "meltdown" high use then the drive firmware may never take the time to do "Spring cleaning". ( Firmware that is expecting a more pedestrian pace may wait for an 'open' window. Firmware that expects to be hammered 24/7 will take steps to weave that in. )



A sanity check though would be to get access to the S.M.A.R.T. data before fail next time and it is really wear or some other condition ( heat , flakey NAND chips , etc.) that is driving the failure. Drive present dead when the drive metadata gets borked also.
 

AidenShaw

macrumors P6
Feb 8, 2003
18,628
4,628
The Peninsula
Thanks. It all makes sense.
Need to break the habit of filling disks to 90%.
And get in the habit of regularly running S.M.A.R.T. or drive vendor tools to check the health of the drive. They often give lots of warning that the drive is having problems - particularly for FLASH wear issues.

Samsung's "Magician" is great for Samsung drives - but it only runs on popular operating systems. On my home workstation it shows
850-2TB.jpg

for the SSD with the OS partition.

If I click on the "S.M.A.R.T.", I see lots of details about internal error and log counters. They can be frightening - drives get and recover from lots of errors. In particular, that 2 TB Samsung had two bad regions from the first week. They were recovered and replaced from the spare pool - but I still see those two fatal errors in the S.M.A.R.T. data every time I look.

(And if you wonder why a 2 TB drive only has 700 GiB of data - let's just say that I'm into extreme over-provisioning even though TRIM is supported at all levels of the filesystems and volume managers.)
 
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bsbeamer

macrumors 68040
Sep 19, 2012
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DriveDx on Mac side is great tool for monitoring drive health. Also builds in referential history to predict possible issues with both HDD and SDD. Works with external drives too, if you enable. This and Carbon Copy Cloner are two of my “must” tools.
 
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haralds

macrumors 65816
Original poster
Jan 3, 2014
1,176
354
Silicon Valley, CA
I use SMARTReporter for menu monitoring and alarms and Disk Sensei for detail stuff.
CarbonCopy Cloner has been with me since its first beta!
[doublepost=1538329917][/doublepost]
DriveDx on Mac side is great tool for monitoring drive health. Also builds in referential history to predict possible issues with both HDD and SDD. Works with external drives too, if you enable. This and Carbon Copy Cloner are two of my “must” tools.
DriveDX does look good! But it just crashed on Mojave...
 
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