What to do with an old SSD?

[Havin_it]

Hi,

This is a bit of a vague question I'm afraid, but I'm totally rudderless on this one and would welcome any inspirational suggestions

When my old netbook died, I found myself with an oldish, low-spec SSD (Kingston V+ 100 96GB SATA2) without a home. I've hooked it up to my home server using an eSATA enclosure (necessary to retrieve its contents) but I can't think what to actually use it for.

The only benchmark of its performance I've really tried is hdparm -Tt and some simple timed writes using dd. Set against the server's main storage (ext4 on a 3-drive RAID5 array on WD Scorpio Blue HDDs), it reads only a slight bit faster, but writes up to twice as fast (with the buffer bumped up a bit).

I'm just not sure whether performance like this makes it much use as any sort of cache device (the only use that came to mind so far) but I'm also not sure how representative those crude benchmarks were, so any suggestions on useful methodology would also be welcome (can be specific to the uses you suggest). I've had a quick look at iozone and run it in both devices, but the results are pretty impenetrable to me

I have an ext4 partition (the netbook's old root partition) on the drive, plus some unused space. All of that is disposable now, soo I'm happy to rejig things for the sake of trying stuff out if required.

Thanks in advance?

[amospalla]

That old ssd has incomparable faster access time than your raid5, the real change that came with ssd storage is not it's maximum speed, but it's access time: put on it things you use daily, specially things you load a lot and or have lots of random disk access, like root, usr, portage, home (not including static content), etc ....

Another option is to use as cache, using some of the new technologies on linux (I can think of bcache) to accelerate your bigger raid5.

I hope you get the idea.

[NeddySeagoon]

Havin_it,

The read difference between SSD and rotating rust is latency. The SSD has almost zero latency. HDD have to seek to the track where you data is, then on average, wait half a revolution of the platter for your data to come under the read head. The latency is all dead time for data transfers.
True, the HDD and the OS both try to guess what you want to read next, so the data is cached in anticipation.

SSDs card read as fast as the memory chips allow. Higher speeds are achiever by reading more memory chips in parallel. The spinning HDD reads bits sequentially from the platter.

I'm with amospalla on how to use it.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[Havin_it]

Thanks both for the replies (and sorry I've left this unanswered for a while)

bcache sounds like maybe the best use (being sort of an across-the-board improvement) but I guess I'll need to swot up on it a bit.

A couple of other possibilities occurred:

* Swap space
* External journals for the Ext4 partitions
* Data partition for dirs where lots of file reading happens rapidly ($PORTAGE_TMPDIR springs to mind)

Most of these don't require that much space though; would it be unwise/counterproductive to use it for more than one of these things?

[Simba7]

If you're using ZFS, you can use it as an L2ARC cache.

[amospalla]

I suggest you moving your entire system to that ssd, but keeping on the mechanical disks big files like multimedia (image, audio and videos), first because they are big, and second because those are not being constantly accessed and/or used, and for example, listening to music or viewing a video does not benefit at all from being on a ssd.

This way, the computer will be blazing fast from boot, to day to day load and use of programs.

Even with a standard use of your computer, it is easy that you don't get to fill the ssd.

[Havin_it]