Sign in to follow this  

trim/garbage collection + audio/video production build advice/info.

Recommended Posts

Never used any SSD's before! So may I ask,

What activates/triggers trim and/or garbage collection?

Is trim and garbage collection the same thing?

Can either and/or both be controlled manually or adjusted in some way?

The reason I ask is because I would like use SSD's in a Audio/Video production computer build but I'm concerned about Program/Erase Cycles.

I think, I'd like to have a SSD dedicated for Video Editing and another SSD dedicated for Audio Recording and etc... (OS/Programs on separate SSD)

Is this possible? If so, how would and/or should the drives be arranged/configured, setup?

The drives that I have on hand now: SSD's = 3-Samsung 850 EVO 250GB and 1-Samsung 850 EVO 500GB. HDD's = 1- 4TB WD Black, 2-1TB WD Blacks and 4- 500GB WD Blacks (all 7200RPM)

I know the SSD's aren't very big (250GB,500GB) but...?

As far as Video footage goes nothing fancy, no 2K or 4K stuff video footage would be 1920x1080p Res., Bit Rate = 24Mbps, 30Fps, h.264 (little canon Vixia HF R600)

Don't plan on being the next Universal Studios, etc... but still can't say how much Video footage I would be Loading/Editing on one of the SSD's per day, week, month, year, yada yada.

As far as Audio, thought is SSD would have lower Latencies and increase Track Count, plus possibly SSD also good for Sample Drive (VST's)? 

Thanks in advance to all and appreciate all thoughts, advice and help!!!

Peace, dude1


Edited by dude1

Share this post

Link to post
Share on other sites

"Garbage collection" refers to software rather than drives. When a program no longer has use for variable space (usually strings or arrays) then that storage space becomes "garbage". Garbage collection refers to releasing that space to the memory manager for reuse. The user cannot do anything about garbage collection. The app developer has to do that, and the OS developer can provide tools to make it easier.

"Trim" is a function used to help SSDs remain efficient. If you delete a file, the OS usually only wipes the filesystem directory entry and updates the bitmap to show those blocks are free space. The OS doesn't usually write zeroes to the blocks that the file used to occupy, because this would take time; the computer would act slower.

However, the SSD is independent of any particular OS or filesystem. It doesn't know how to read directory entries or volume bitmaps. It keeps its' own map of blocks that have been written to, but internal SSD blocks are big. Say, 32 MB big. These are the smallest "zones" that an SSD can erase. Unlike a hard drive, an SSD cannot erase standard 512-byte blocks at will. Only relatively huge blocks.

When it comes time to modify contents in an internal block, the SSD must do a dance. All unchanged data has to be copied to a standby block, along with the modified data. The old block is then erased and becomes a standby block. All of this takes time. If the SSD is running low on standby blocks (overprovisioning), it can take a lot of time for the SSD to consolidate used space into fewer blocks.

Trim works by letting the OS notify the SSD that a particular space is actually free. Although data has been written to that space in the past, it should now be disregarded. When the SSD has to manage it's internal blocks, that space need not be copied.

If the OS and SSD both support Trim, then it works automatically. Whenever a filesystem block is freed up, Trim passes the info to the SSD. The SSD uses the info to act more efficiently, which the user sees as the SSD running faster.

As to your last question about Trim, the user could turn it off. But who would want to. A utility could be used to read an existing filesystem, then send Trim notices for every free block in the file system. This would be useful if the SSD had previously been used with an OS that didn't support Trim. Such OSes are in the past today, so such a utility wouldn't do anything.

Edited by reader50
tidy some prose

Share this post

Link to post
Share on other sites

reader50, thanks for your reply

Nice informative answer to the trim and garbage collection, thank you! (I know because I've read on SSD's) and you would have too know something about them, to briefly say it as cohesively as you just did, thanks for that!

In your post where it says: (When it comes time to modify contents in an internal block) 4th paragraph, 1st line.

When is that time?

Thanks Again    Peace, dude1

Share this post

Link to post
Share on other sites

When you save an updated file. Or the OS appends a log file. The change may be trivial from your perspective (perhaps only a few bits altered) but the SSD cannot erase/rewrite tiny spaces. Only the huge internal blocks.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this