Wearing Out my SSD, 37GB written in 10 hours

imorton

macrumors 6502
Original poster
Aug 21, 2010
275
22
Hi Guys, quick question. I just noticed that in the Activity Monitor it shows that in the "data written" section that I have written 37.44 GB in a 12 hour period.

Wow, 37.44 GB written in @10 hours of use, and I didn't do anything "write intensive" other that have Mail, Safari (5 tabs open), and BackBlaze running (it had finished uploading my computer 2 day previous).

At this rate, I would be writing @ 75 GB a day and I know that SSD's have a limited amount of lifetime writes :(

Can anyone enlighten me on these numbers and see what is being written?

Note: Apparently SSD's are good for a limited number of writes, some figure like 10 TB, so at this rate my 250Gb SSD 840 Evo would wear out in short time.. :(

Anyone
 

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MacUser2525

macrumors 68020
Mar 17, 2007
2,006
310
Canada
SSDs are rated in thousands of cycles ie. a complete write of the drive is considered a cycle. In your case roughly 3.5 days per cycle if your drive is rated for 1000 cycles then you have 3500 days at your current rate or roughly 10 years to go. BTW I see nothing there in that picture that shows/says per day total could be since last boot...
 

imorton

macrumors 6502
Original poster
Aug 21, 2010
275
22
SSDs are rated in thousands of cycles ie. a complete write of the drive is considered a cycle. In your case roughly 3.5 days per cycle if your drive is rated for 1000 cycles then you have 3500 days at your current rate or roughly 10 years to go. BTW I see nothing there in that picture that shows/says per day total could be since last boot...
I looked in About This Mac and saw that it shows your last reboot time, and I noticed that in the attached jpg, the Activity Monitor shows how much data was written or read since your last boot-up.

It just seems alarming that in a 10 hour period that I wrote 37Gb and I wasn't doing anything write intensive?

Hmmmm…. :)
 
Last edited:

biglipps66

macrumors member
Mar 11, 2012
60
15
Ive used SSDs since theyve been on the market and have yet to wear one out. Write away to your hearts desire!
 

Gav2k

macrumors G3
Jul 24, 2009
9,217
1,606
Remember it generally won't 'just fail' that'll only be the result if the controller fails.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
30,463
10,272
California
I looked in About This Mac and saw that it shows your last reboot time, and I noticed that in the attached jpg, the Activity Monitor shows how much data was written or read since your last boot-up.

It just seems alarming that in a 10 hour period that I wrote 37Gb and I was doing anything write intensive?
I agree, that is odd for the usage you describe.

Were you running any kind of backup or copy to external drives? Just from a quick test I did here it looks like that data read/write total is for all local drives. So if you did a 20GB Time Machine backup to a local USB drive that would increase the data written by 20GB.

There is a good article here with some lifespan data on your EVO drive. Yours would be that 23.4 years to the right at 10GB per day.

 

dusk007

macrumors 68040
Dec 5, 2009
3,386
62
BTW if that isn't clear that number is from all writes. That includes backups and flash drives. Your timemachine backs up 7GB to the external that is 7GB more for the stat but no write on the ssd.
Most of the writes probably come from streaming cache (youtube and such), downloading, unpacking archives or installing stuff.

Don't worry on a 256GB SSD you'd really have to write a lot of data and every single day. Wear out was an issue with 32GB and such small SSDs. 256GB can handle 8 times the writes assuming individual cell last as long.

Someone also put some ssd into a system and continously wrote data for months. He found that most of the nand cells out live the specifications (3000 cycles or 1000 and so on) by sometimes 4-5 times. The cycles is more a minimum the manufacturer guarantees. Cells are turned off if there are too many errors it won't just count down from 1000 to 0 and shut it down even if it was still good.

Short story you aren't going to wear out your 250GB SSD. A few other parts in the notebook are likely to fail far sooner. The controller of the SSD might fail before the nand does.
 

Freyqq

macrumors 601
Dec 13, 2004
4,022
172
Yeah, I wouldn't worry about it unless you are using it as a cache drive for huge photoshop files or something intensive like that. You would have to do those kinds of writes every day for years to affect performance. Also, as I understand it, when they wear out they simply can't be written to anymore. So, the data is safe in a read-only mode. It is just unusable as a boot drive.
 

imorton

macrumors 6502
Original poster
Aug 21, 2010
275
22
I guess like you all say, just use it and if eventually the drive becomes worn with "less useable nand cells", I'll just get a 2 Tb SSD than for $150… :)

I was just curious how the Activity Monitor could show how I went through 50Gb of data written in one day.

IAN.
 

imorton

macrumors 6502
Original poster
Aug 21, 2010
275
22
I guess like you all say, just use it and if eventually the drive becomes worn with "less useable nand cells", I'll just get a 2 Tb SSD than for $150… :)

I was just curious how the Activity Monitor could show how I went through 50Gb of data written in one day.

IAN.
I just noticed that it appears to be BackBlaze that is causing all these "writes". My initial backup to them finished last week, so I will try to use their scheduling feature to reduce the constant disk trashing.. :)

IAN
 

MacModMachine

macrumors 68020
Apr 3, 2009
2,278
153
Canada
Ive used SSDs since theyve been on the market and have yet to wear one out. Write away to your hearts desire!
me too , i have 2 240gb ssd's in my ESXi server and both run 3-4 os's and they still have not given up.

i was expecting them to wear out every 8-12 months, I'm on month 13
 

imorton

macrumors 6502
Original poster
Aug 21, 2010
275
22
me too , i have 2 240gb ssd's in my ESXi server and both run 3-4 os's and they still have not given up.

i was expecting them to wear out every 8-12 months, I'm on month 13
Wow, your SSD's wearing out in 8-12 months…. :(

I was hoping to get 5-7 years out of mine, but I checked my Disk Activity this morning and I have written @ 60Gb in a 24 hr period. Good thing I am not running a data intensive application or server :)

IAN
 

RyanG

macrumors 6502
Sep 18, 2007
497
31
me too , i have 2 240gb ssd's in my ESXi server and both run 3-4 os's and they still have not given up.

i was expecting them to wear out every 8-12 months, I'm on month 13
Pretty uneducated about SSD's it seems. No worries, most are but anticipating death within 8-12 months is stupid.

I have some old vertex 2's still kicking hard. SSD's are a lot more durable than people think.
 

MacModMachine

macrumors 68020
Apr 3, 2009
2,278
153
Canada
Pretty uneducated about SSD's it seems. No worries, most are but anticipating death within 8-12 months is stupid.

I have some old vertex 2's still kicking hard. SSD's are a lot more durable than people think.
its not stupid....with 3-4 virtual machines running it writes TB's per day.


do some research.
 
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