Defragment ssd discussion

[Joe Yahchouchi]

Hello.

Yes I know that "you shouldn't defragment ssd" and that writes degrade the ssd and that ssd supposedly don't care where the data is located. However, I take issue with that last argument. All ssd benchmarks show that ssds perform at least twice as fast when reading data sequentially than randomly. And to me that seems like ssds care, at least a fair amount, about how data is located on it.

With that in mind, isn't it at all beneficial to defragment at least once a year? (or in my case a year and a half, ssd showing 100% fragmentation after I used compression) And I really don't care about ssd lifetime(I don't do much writes anyway)

 

[SonSon1]

As long as you do it every year or year and a half, you won't wear it down enough before it's time to upgrade it. You would get better results though if you reinstalled your OS in the same time frame, less SSD wear and a cleaner system at the same time.

 

[Joe Yahchouchi]

But is it agreed that there is a performance gain in defragmenting in some cases?

 

[giantbucket]

there might be a small hit from fragmentation, but i think the much larger hit is from the fact that 1000 files of 4k each means 1000 entries in the TOC, whereas 10 files of 400k each means 10 entries in the TOC. no matter what, it takes a finite amount of time to read the data, whether it's the data you want or the TOC that tells it where the data is in the first place, and it may very well be that this TOC is a much bigger hit than simply fragmentation.

but yeah, defrag an SSD every so often and it's fine. heck, i degragged one when i needed to shrink a partition on it. i think if you do it WEEKLY like on an old-school schedule it's a bit overkill and might wear out the drive sooner, but once a year is a drop in the bucket.

 

[Archaic59]

No. Here is a guy who tried several defrag progs and none of them posted gains worth the time, trouble, and write degredation on the drive. In the end, it was found that it's best to tweak the ssd upon installation and make sure trim is enabled, and then leave it alone.

http://www.pcworld.com/article/2047513/fragging-wonderful-the-truth-about-defragging-your-ssd.html?page=2

 

[rhysiam]

You realise that the reason an SSD is so fast at sequential transfers is because it's got a whole bunch of channels onboard with their own NAND, and it's effectively splitting the writes up across all the available channels. This is why smaller capacity SSDs (sometimes) have lower sequential read & write performance... because they have fewer channels to stripe the commands across. It's actually fairly similar to RAID 0.

My understanding (and on this I'll admit I'm not so confident) is that the reason random writes/reads are slower is not because they're fragmented, but because the sheer overheads associated with processing that amount of information becomes the bottleneck. The bottleneck shifts from the NAND itself (or the SATA3), to the IOPS of the drive, which is limited by the controller's processing ability as well as the NAND itself.

SSDs are so fast because they're fragmented.

 

[Joe Yahchouchi]

I defragmented my drive, there was no noticable improvement as far as I could tell on reads. Did not yet test on writes. I don't know whether it was worth it or not, but it makes me feel better when it does not say "100% fragmented" it's already 2 years old, if it lives another 2 years it's enough for me.