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Sandisk SSD Plus write amplification

 
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post #1 of 8 (permalink) Old 09-11-2015, 02:54 AM - Thread Starter
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In the space of 2 days my SSD suddenly has huge write amplification.

According to cystaldiskinfo log

Host Writes went from 469 to 565
Nand Writes went from 565 to 7349

Its my OS drive and no special programs running yet it just keeps increasing . Like right now writing this post its now increase to 7379. It only just started acting like this. Is there a problem here?


(1) SanDisk SDSSDA240G
Model : SanDisk SDSSDA240G
Firmware : Z22000RL
Serial Number :
Disk Size : 240.0 GB (8.4/137.4/240.0/240.0)
Buffer Size : Unknown
Queue Depth : 32
# of Sectors : 468862128
Rotation Rate : ---- (SSD)
Interface : Serial ATA
Major Version : ACS-2
Minor Version : ACS-2 Revision 3
Transfer Mode : SATA/600 | SATA/600
Power On Hours : 79 hours
Power On Count : 203 count
Host Reads : 578 GB
Host Writes : 537 GB
NAND Writes : 7356 GB
Temperature : 41 C (105 F)
Health Status : Good (100 %)
Features : S.M.A.R.T., APM, 48bit LBA, NCQ, TRIM, DevSleep
APM Level : 0000h [OFF]
AAM Level : ----

-- S.M.A.R.T.
ID Cur Wor Thr RawValues(6) Attribute Name
05 100 100 __0 000000000000 Reallocated Block Count
09 _79 100 __0 00000000004F Power On Hours
0C 100 100 __0 0000000000CB Power Cycle Count
A6 100 100 __0 000000000003 Min W/E Cycle
A7 100 100 __0 000000000000 Max Bad Block/Die
A8 100 100 __0 000000000037 Maximum Erase Cycle
A9 100 100 __0 000000000010 Total Bad Block
AA 100 100 __0 000000000000 Vendor Specific
AB 100 100 __0 000000000000 Program Fail Count
AC 100 100 __0 000000000000 Erase Fail Count
AD 100 100 __0 00000000001F Average Erase Cycle
AE 100 100 __0 00000000000A Unexpected Power Loss Count
BB 100 100 __0 000000000000 Reported Uncorrectable Errors
C2 _59 100 __0 003300000029 Temperature
C7 100 100 __0 000000000000 Vendor Specific
E6 100 100 __4 000000000001 Percentage Total P/E Count
E8 100 100 __0 000000000064 Spare Block Remaining
E9 100 100 __0 000000001CBC Total GB Written To NAND
F1 253 253 __0 000000000219 Total GB Written
F2 253 253 __0 000000000242 Total GB Read
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post #2 of 8 (permalink) Old 09-11-2015, 06:04 AM
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Asuming the reading is correct there are some possibilities:
*garbage collection, especially since you say it rises while you post on OCN, thus while the SSD is mostly idle
*failing NAND chip, thus the data is copied somewhere else ==> it should impact performance (less spare area), so you can check with a benchmark

Anyone else with ideas?

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post #3 of 8 (permalink) Old 09-11-2015, 07:48 AM - Thread Starter
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Well i've had it less than a month, maybe it took a few weeks of use before the wear levelling kicked in ?

Still its a lot more nand writes than im used too, will be interested to see if it settles down.

It still benches normally.

I know this drive has one of the cheap dramless controllers SM2446XT so maybe this is a drawback of that.
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post #4 of 8 (permalink) Old 09-14-2015, 07:35 AM - Thread Starter
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After chewing through NAND writes and erase cycles at a crazy rate it finally stopped when I freed up a lot of drive space.

Despite already having 120G free, I freed up 180G and the write counter immediately stopped increasing. i then copied the data back and the problem hasn't come back.

So let that be a warning to those with this drive!

This is where it ended up, In the time the problem existed 100GB of writes was amplified to 17000GB written to NAND

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post #5 of 8 (permalink) Old 05-17-2016, 12:57 AM
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Quote:
Originally Posted by gooly View Post

After chewing through NAND writes and erase cycles at a crazy rate it finally stopped when I freed up a lot of drive space.

Despite already having 120G free, I freed up 180G and the write counter immediately stopped increasing. i then copied the data back and the problem hasn't come back.

So let that be a warning to those with this drive!

This is where it ended up, In the time the problem existed 100GB of writes was amplified to 17000GB written to NAND


hi man,

what is your motherboard model?
I think I have notced a link between the chipset model and motherbpard chipset. Only one type of chipset (nvidia) causes that problem) in my 6-7 pcs using SSD Plus from Sandisk. Wonder if that is the cause.
In your case you have a sata3 board so is much more recent than mine.
Thanks for posting your mobo reference for knowledge smile.gif


PS: I'd love to test your method but the disk is 120 Gb and only contains the system... so can 't remove much data and copy it back..

* Z97 Pro Gamer / i7-4790k @ 4.6 1.23V / LEPA 240 push-pull / 4 x 2 Go 2000 @ 8-10-8-28-1T
- Mobos 775: EP45T-UD3R, EP45T-EXTREME, EP45 UD3P, X38-DQ6, P35-DS4, ...
- Mobo Z97: Asus M7I, M7G, M7R
- Mobo Z77: M5F, M5G
- DDR2 and DDR3... tons.....
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post #6 of 8 (permalink) Old 05-17-2016, 06:05 AM - Thread Starter
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Quote:
Originally Posted by bolc View Post

hi man,

what is your motherboard model?
I think I have notced a link between the chipset model and motherbpard chipset. Only one type of chipset (nvidia) causes that problem) in my 6-7 pcs using SSD Plus from Sandisk. Wonder if that is the cause.
In your case you have a sata3 board so is much more recent than mine.
Thanks for posting your mobo reference for knowledge smile.gif


PS: I'd love to test your method but the disk is 120 Gb and only contains the system... so can 't remove much data and copy it back..


I've changed PC now but was using Intel H77 or Z77 based motherboard at the time
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post #7 of 8 (permalink) Old 05-19-2016, 05:50 AM
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maybe the firmware is reporting incorrect nand writes. In any case, i wouldn't worry about it. thumb.gif

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post #8 of 8 (permalink) Old 05-19-2016, 06:25 AM
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Originally Posted by hojnikb View Post

maybe the firmware is reporting incorrect nand writes. In any case, i wouldn't worry about it. thumb.gif

I doubt since the nand write was fine on a ich10r board but slowly going up (waf of 4 for 2000 gb nand, 460 gb host write). Switching to another board, it went up very fast, right now at 10 Tb nand write for 490 gb host...

* Z97 Pro Gamer / i7-4790k @ 4.6 1.23V / LEPA 240 push-pull / 4 x 2 Go 2000 @ 8-10-8-28-1T
- Mobos 775: EP45T-UD3R, EP45T-EXTREME, EP45 UD3P, X38-DQ6, P35-DS4, ...
- Mobo Z97: Asus M7I, M7G, M7R
- Mobo Z77: M5F, M5G
- DDR2 and DDR3... tons.....
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