SSD heavy writing life?

I am going to buy. Corsair P256. This will be my first SSD.

I know SSD is okay with reading, but writing will hurt SSD's life. My question is if I divide this 256GB drive to 3 partitions: 50GB/100GB/100GB. And If every two days, I copy and delete a 20GB file on a 100GB partition. How long do I expect this drive to last?

Also, my laptop has 8GB memory. If I enable window hibernation, will the SSD drive die sooner?

Thanks.

 

the drive is treated as one so partition doesn't affect anything.

also the life depends on the nature of write. If you are doing it like say one big 20G file, it would mean a WA factor of 1, that would significantly improve the life span.

In other words, if your write is sequential in nature (write 20G, delete then write 20G again), the lifespan can be easily calculated based on P/E cycle. So for NAND with 10000 cycle, that would be 10000 days if you do it once a day.

 

For some drives (I don't know about the Corsair P256), the NAND till possible failure has come to 5000 or even 3000 cycles.

Also, what about TRIM and garbage collection? Might that double the writes on the drive?

 

I don't know about specific NAND P/E cycle, I was only saying how to calculate that.

TRIM doesn't cause any write, it is informational to the controller.

I was talking about 'sequential' access so neither TRIM of GC plays a role.

What I wanted to say was the life span of a SSD depends on how it is used. If it is used in a manner that results in WA of 1, it is just the P/E cycle. Or the total size x PE cycle / write per day

 

OP said something about deleting the file. Won't that invoke TRIM?
Are you quite sure that TRIM doesn't write anything to the drive?

 

DELETE doesn't cause any WRITE. If TRIM is supported, it would be passed to the controller. A usage scenario like this is optimal to the SSD resulting in WA of 1.

TRIM is an ATA command, not a write and yes I am very very sure.

edit:

DELETE does change the data but those are neglible write comparing with the 20G

 

Is 10000 cycles for MLC SSD, or SLC SSD?

"WA of 1"? What does it mean?

The 20GB files I talked about are different VMWare machines. I do a lot software testing. Most of time, after testing a software (1-2 days) I delete the VMWare and recover with the copy before the testing software was installed.


So, how long should I expect the SSD to last? 10-15 years or 3-5 years. It seems Corsair P256 is an OEM version of Samsung SSD 256GB.

 

I think by WA he means Write Amplification, which happens due to the nature of how SSDs have to delete in larger blocks than they can write. If you need a bit of a refresher course, there's always the old Anandtech SSD article.

So, in theory, given a write amplification level of 1 (not practical, but we'll assume it for best case numbers), 10,000 write cycles for MLC NAND over 256 GB would result in 2,560,000 GB write cycles. If you wrote 20 GB a day, that would then become 128,000 days, or about 350 years. The problem is, of course, with write amplification, the actual time will be cut down, because for every 20 GB you think you write, you're actually probably writing rather more than that. And it gets even worse when (over)writing small files, since you have to erase an entire block to write a small file. There's also the matter of overprovisioning; most SSDs have more storage space than they actually advertise, as in, that 256 GB drive probably has an extra 20 GB or so for added wear-leveling and GC space. That will also end up affecting the lifetime of the drive. In the end, the question really comes down to how well the controller is implemented (which affects how much write amplification is actually involved), how good the drive is at wear-leveling, and the quality of the NAND (part of the reason Sandforce controllers are popular is their Dura-write and compression, which in theory lets you use cheaper, lower quality NAND with less write cycles and achieve the performance of more expensive NAND). The problem is, of course, that manufacturers are reluctant to hand out this sort of information.

In the end, it comes down to how much data you generally write to your drive.

 

I just took a look at the spec sheet for my SSD and the manufacturer lists endurance as 35.1 years at 50 GB write/erase per day. No note on how they calculated that, so I take it with a heavy grain of salt.

 

WUXGA,

With your usage pattern, I would not be expecting the drive to last for much longer than a year or two.

Not only are you writing a 'sequential' file of 20GB, you are also updating/modifying it too in-between. Your actual writes to the drive will be much higher than 20GB per day - I'm guessing:

1) Copy 20GB 'master' = 20GB

2) Use copy for 2 days = 5 - 10GB (just guessing, of course - but taking the bad WA Samsung drives are noted for into account)

3) Delete 20GB copy = 20GB (If TRIM or GC are working properly)

4) Copy Master again = 20GB


The above is a best case scenario - we are not taking all the writes that the host O/S is making too.

The SSD should greatly increase your VM performance, so not getting an SSD is not an option: what I would be more in tune to is the fact that this setup needs to be backed up daily and religiously.

With an average daily write of 35GB (minimum), I don't think the Samsung is up to that kind of abuse when long term reliability is the goal.

Good luck.

 

My 120GB Vertex SSD shows an average of 111 cycles written over 164GB. It's being used as an OS drive. I have used procmon.exe to monitor all file writes and moved pretty much every movable folder containing frequent written items like caches to RAMDisk. Still, the WA value would be something like 80. Then the manufacturer says you can write 10000 * 120GB to the drive before it dying, which is a total blatant lie - more like 10000 * 120 GB / 80.

 

Thanks Everybody!

Now I really worry about SSD's reliabilities...

 

Deleting a large file does not write the whole 20GB, it would just mark under the file system that no data was there anymore.

It would not write to the cells untill you actually wrote data there.

Also the Sandforce drives use real time compression, if the data you work with is compressable your writes will actually much less.

 

the way I understand it, trim/garbage collection will write to the drive to clear the area where the data was so that there is no performance penalty next time there is a write to that area.

 

My advice is buy a drive with a decent warrenty, intel drives are pretty reliable and should last a long time. Sandforce drives are good if your data is compressable.

Now as for backing up your data you should do that anyway. However if your drive writes are exhausted then it does not stop working. It will just refuse to write, you can still copy the data onto a fresh drive and continue working.

 

But it only does that to partially full cells.

If you have one block of 20GB data and delete it, there is no garbage except maybe the start and end cells.

Garbage is when a cell has data you want to KEEP in it, and then you want to put some more info into it. If the cell contains no data in it you want to keep you make just a single write.