ssd and unallocated space

[lenjack]

What is the proper amount of unallocated space to leave on an 240GB ssd running W7, with nothing very intensive on it. Only 49.5% used.

 

[GlacierFreeze]

Nothing very intensive? Allocate it all.

 

[lenjack]

Thanks for the extremely quick response. Would you mind expanding on that?

 

[PliotronX]

If you can spare it, the more that you leave unallocated the better but the point of diminishing returns is fast after ~8%. 240GB drives already have ~16GB overprovisioned (6%) so you shouldn't have to worry about it and just use as much as you'd like especially if there aren't a crazy amount of writes going on.

 

[Elixer]

Thanks for the extremely quick response. Would you mind expanding on that?

The SSD already has reserved space, in your case, with such light usage, there isn't really a need to over provision more free space.

 

[AlienTech]

Actually you dont need to leave any free space. The drive will provision the free space so it does not have to do it when you write data, so leave a few gigs.. The amount of data you can write does not increase. Remember, the old data gets written to a new location to every cell has an even wear leveling. New data gets written to the free space and old data is then moved to recently freed up areas and the area where that old data used to reside, would now be where new data is written. No matter how much you play around, 50% of the life cycle would be lost this way and there is not much you can do. To get an extra 25% on top of that you would need to leave half the drive empty.. Checking my own SSD I notice that the wear leveling is around 4, which means for every byte I write, 4 bytes are written and thats a huge write amplification.. Yet after 2 years and 20TB written, it is still above 90% of life left.. So the drive actually wrote 100TB to the nand already and used up 10% of life.. I am not sure it would be worth it for me to leave a lot of empty space as it would not have helped the drive last much longer.. not much difference between 90% or 95% of life left.. That would still leave another 10 years. Would the drive even last 5 years? Hard drives begin to fail around that point no matter how careful you are.

 

[Charlie98]

I would allocate all of it, but leave at least 20% of the allocated space free of data. Particularly older, smaller SSDs took a performance hit if they were almost full (I proved this with my OCZ 60GB Agility3, performance went in the toilet at about 85%...) I don't know if the newer, bigger (>250GB) SSDs still suffer this fate, but I continue to leave 20% free on all my SSDs.

 

[GlacierFreeze]

Thanks for the extremely quick response. Would you mind expanding on that?

If you can spare it, the more that you leave unallocated the better but the point of diminishing returns is fast after ~8%. 240GB drives already have ~16GB overprovisioned (6%) so you shouldn't have to worry about it and just use as much as you'd like especially if there aren't a crazy amount of writes going on.

This. And with moderate usage, the memory endurance will last a couple decades. No reason to worry about wearing it out. Put whatever you want on it and enjoy the Read/Write speeds!

In almost 2 years, I've used only about 5% of the endurance on mine. Will probably be upgrading this system for a newer one within the next year or two and recycling this drive into it. It'll last a long time. Still always a good idea to keep important stuff backed up though.

 

[VirtualLarry]

but I continue to leave 80% free on all my SSDs.

No offense, but that's crazy talk. Given how expensive SSDs are, I just can't imagine having to purchase a 1TB SSD, just to be able to store 200GB on it.

 

[Essence_of_War]

I would allocate all of it, but leave at least 80% of the allocated space free of data.

That has to be a typo, right?

 

[GlacierFreeze]

I think he meant can use 80% but leave 20% free.

 

[Charlie98]

That has to be a typo, right?

Yep, sorry about that... ...20% free space.

I need another cup of coffee...

 

[Essence_of_War]

Heh heh, very good, I concur then!

 

[VirtualLarry]

LOL. Sorry about raking you over the coals on that one. Leaving 20% unused is a good strategy.

 

[BonzaiDuck]

LOL. Sorry about raking you over the coals on that one. Leaving 20% unused is a good strategy.

Even for that and to which I agree, I like my boot/system drives only half-full and I get antsy when used capacity is going over 75%.

 

[Charlie98]

Even for that and to which I agree, I like my boot/system drives only half-full and I get antsy when used capacity is going over 75%.

I bought a 'huge' 512GB M550 for the gamer upstairs... it's at 374GB/102GB now... and I'm starting to get twitchy. D:

 

[imagoon]

LOL. Sorry about raking you over the coals on that one. Leaving 20% unused is a good strategy.

Actually it is 20% waste. The SSD already has spare area. The flash is 256GB only 240GB is allocated by the firmware. For a home user, 16GB of spare area is typically enough.

Obviously you should have free room on a boot volume but there is little reason to leave 48GB unused.

 

[VirtualLarry]

Actually it is 20% waste. The SSD already has spare area. The flash is 256GB only 240GB is allocated by the firmware. For a home user, 16GB of spare area is typically enough.

Obviously you should have free room on a boot volume but there is little reason to leave 48GB unused.

My friend had a 30GB OCZ Agility SSD that I gave him, with Win7 64-bit on it. With only 3GB free, he was getting "pauses" with his system, because the SSD was constantly having to re-arrange and free up blocks to write to. Yes, even with the built-in "spare area".

So, sometimes, if you want maximum performance AND longevity from your SSD, it would be wise to over-provision the spare area somewhat.

 

[imagoon]

My friend had a 30GB OCZ Agility SSD that I gave him, with Win7 64-bit on it. With only 3GB free, he was getting "pauses" with his system, because the SSD was constantly having to re-arrange and free up blocks to write to. Yes, even with the built-in "spare area".

So, sometimes, if you want maximum performance AND longevity from your SSD, it would be wise to over-provision the spare area somewhat.

If this was true, then TRIM wasn't working. Otherwise you claim make no sense, the firmware was poor on that drive or the drive was defective. The spare area is always free for the drive to clear. It is up to the firmware to actually do anything. Sure more empty space will mask these issues as the odds are higher that you will hit a free spot but it also wastes capacity. SSD's really are not that complex of the device. They really don't need all the dark arts that people seem to think they do.

 

[Charlie98]

If this was true, then TRIM wasn't working. Otherwise you claim make no sense, the firmware was poor on that drive or the drive was defective. The spare area is always free for the drive to clear. It is up to the firmware to actually do anything.

I can ditto Larry's friend's Agility performance degradation. Once I replaced it with a larger drive, I wiped the Agility and put it in my HTPC as the boot drive... with only 30% used capacity, it ran like my new Samsung 840Pro 256GB that replaced it (in real world use, not benchmarks, of course.) Not defective, not bad FW... just a very small SSD. I think the problem is more magnified on the smaller GB SSD vs the larger ones, for obvious reasons... As I understand it, some SSDs have more OP/replacement memory than others, I still wouldn't want to run even a modern big GB SSD at 95%.

 

[BFG10K]

What is the proper amount of unallocated space to leave on an 240GB ssd running W7, with nothing very intensive on it. Only 49.5% used.

None - fill it up and partition it exactly like an HDD if you need to. Why pay 10x more per GB just so you can molly-coddle it?

If it can't take 240GB, it's false advertising.

 

[imagoon]

I can ditto Larry's friend's Agility performance degradation. Once I replaced it with a larger drive, I wiped the Agility and put it in my HTPC as the boot drive... with only 30% used capacity, it ran like my new Samsung 840Pro 256GB that replaced it (in real world use, not benchmarks, of course.) Not defective, not bad FW... just a very small SSD. I think the problem is more magnified on the smaller GB SSD vs the larger ones, for obvious reasons... As I understand it, some SSDs have more OP/replacement memory than others, I still wouldn't want to run even a modern big GB SSD at 95%.

I run a few hundred 100GB SSDs @ 100% utilization so can't tell what the defect is with your application. I certainly don't see "stuttering."

--edit--

I also have now for the heck of it gone through the firstr 4 pages of google for "ssd stutter" and all of the fixes have been "enable ACPI, Update drivers, Update BIOS/Firmware,replaced defective drive."

 

[bononos]

Is the 'unallocated space' that is being discussed in this thread the minimum unused space on the ssd or is it something that is set by a vendor tool to define the over-provisioning capacity?

 

[bononos]

I run a few hundred 100GB SSDs @ 100% utilization so can't tell what the defect is with your application. I certainly don't see "stuttering."

--edit--

I also have now for the heck of it gone through the firstr 4 pages of google for "ssd stutter" and all of the fixes have been "enable ACPI, Update drivers, Update BIOS/Firmware,replaced defective drive."

He was using 60Gb drives as an example, and such small drives (due to their cut down memory controller design) are much slower and users will probably feel more pauses compared to bigger drives.

 

[VirtualLarry]

I run a few hundred 100GB SSDs @ 100% utilization so can't tell what the defect is with your application. I certainly don't see "stuttering."

--edit--

I also have now for the heck of it gone through the firstr 4 pages of google for "ssd stutter" and all of the fixes have been "enable ACPI, Update drivers, Update BIOS/Firmware,replaced defective drive."

First of all, the only 100GB Enterprise SSDs that I know of, are Intel 710 series, which actually contain 160GiB of NAND.

Second, you are incorrect that TRIM was not working on my friend's drive. I ran two of them in RAID-0 (no TRIM, I was on ICH9R), and mine degraded so badly, within a week, the RAID-0 of drives was benchmarking far worse than a single drive of that type with TRIM enabled.

TRIM is only advisory. It can be used for the drive to simply "mark" what pages to reclaim when it does a GC pass. Which may only happen at idle times. My friend watches a lot of streaming video online, which streams to a temp file on the drive in the background.
Which means that it wasn't giving the drive idle time, which means that it was exhausting its "free list", and forcing a GC pass to free up blocks, which pauses drive I/O while it's waiting.