Hello,

 

 

I have another question. Since I'm going to buy a new hard disk to replace my f4. I was thinking to upgrade to the pro edition, so I can install a cache drive. But I've got still some questions about that. I was thinking to get the samsung 840 120gb SSD for cache drive. I'm also gonna run plex and crashplan on it since the logging keeps my array awake. And I can't use sleep because it waits 45 minutes after disk spindown. Is this a good idea to get this drive and to run those programs on that ssd cache drive.

 

My second question is a tricky one I guess . I assume my disk array is at idle /spun down when writing files to the server because all files go to the cache drive. So will my unraid server go into sleep while copying to my server (cache drive) since my array is spun down. (I'm using simple features to sleep the machine, after 15min spin down disk, 45 min later put server to sleep, it's the delay  after disk spindown), or shouldn't I focus on the delay after disk spindown (since the cache drive won't spin down" and just set an "Interval of network inactivity".

Or does it also check if there isn't been written/read from the cache drive? If so, it will also never go to sleep because plex and crashplan are logging to this crash drive, or am I wrong? I really need sleep , find it a waste to keep the server up 24/24 7/7 when not using it.

 

And last but not least. Is that 120 gb enough. Saw this:

The final consideration in choosing a cache drive is to think about the amount of data you expect to pass through it. If you write ~10 GBs per day, then any drive 10 GB or larger will do (a 30 GB SSD may be a good fit in this case). If you write 100 GB in one day every few weeks, then you will want a cache drive that is larger than 100 GB. If you attempt a data transfer that is larger than the size of your cache drive, the transfer will fail.

 

Does that mean I can only copy 120gb a day (assuming mover moves once a day) to the server? Or can I copy as much as the array can handle, but am I limited to maximum filesize to 120gb? (I don't have files that are 120gb large. I think I've read somewhere that when cache is full it will go straight to the array.)

 

thanks in advance

 

edit: using unraid 5.11rc with simple features 1.0.11

 

First of all, I had a 830 in my desktop and I upgraded to a 840 pro and used the 830 in my unraid build; all items are 128GB.

 

1. Max of 128GB per day, assuming that you only run the mover once. When the cache drive is full, all transfers will just wait until there's space (If using teracopy) or die (If using window's explorer).

2. If you're only using it 7/7, why not just have it power down? Why sleep? I'd think powering down would be better.

3. Myself, I'd recommend you get 256GB as I often hit the 128GB cap on my SSD and then I have to manually start the mover.

4. I do recommend an SSD over a mover, simply because the SSD is more reliable during the time that it's not protected by the parity, as for the speed increase (between SSD/HDD) you honestly won't notice it over a network.

1. Max of 128GB per day, assuming that you only run the mover once. When the cache drive is full, all transfers will just wait until there's space (If using teracopy) or die (If using window's explorer).

The only way for this to be correct is if you are using the cache drive in a way that was not intended. The original intent was to have a transparent fast buffer for user shares. If you write directly to the cache share folders instead of the cache enabled user share, then yes, you will hit the hard limit. If you write to the user share with cache enabled, it will write to the cache drive until it's full, then start writing directly to the array drives.

 

BTW, this thread would be better in the customization area, as sleep and simplefeatures are not supported by unraid.

1. Max of 128GB per day, assuming that you only run the mover once. When the cache drive is full, all transfers will just wait until there's space (If using teracopy) or die (If using window's explorer).

The only way for this to be correct is if you are using the cache drive in a way that was not intended. The original intent was to have a transparent fast buffer for user shares. If you write directly to the cache share folders instead of the cache enabled user share, then yes, you will hit the hard limit. If you write to the user share with cache enabled, it will write to the cache drive until it's full, then start writing directly to the array drives.

 

BTW, this thread would be better in the customization area, as sleep and simplefeatures are not supported by unraid.

 

Just to prove you wrong (Sorry):-

 

A. Let's go ahead and create a 80GB file on my computer (I only have 81GB free (Stupid 128GB SSD), I'll have to do this in parts):-

 

B. And another 3GB (Server has 4GB free on the cache drive):-

 

C. And now finally another 2GB (1GB over the limit):-

 

Dammit, it's full, if there's something I've done wrong feel free to share, my configuration file for my mounted Z:\ (\\tower\Nicks Files) share:-

(IMAGE REMOVED)

 

 

Did that whole thing and I got proved wrong. Ha. I guess I was wrong, OP, yup, you can transfer unlimited amounts, cache is just a buffer.

 

When I had the error it must have been, well, I don't know. I did have an error before, no idea what I did wrong, works fine now.

Just to prove you wrong (Sorry):-)

 

Did that whole thing and I got proved wrong. Ha. I guess I was wrong, OP, yup, you can transfer unlimited amounts, cache is just a buffer.

 

When I had the error it must have been, well, I don't know. I did have an error before, no idea what I did wrong, works fine now.

Been there, done that. It's a good day, you learned something. If I don't learn 1 new thing each day, I feel like I wasted it.

You might have to set a min free space on the cache for it to not fail as you guys are discussing. It can depend on the program doing the copying. I believe Terracopy tries to allot the whole required space first which forces unRAID to move to an array disk. Using Windows Explorer the 3rd test example would likely fail.

 

I've never experimented with a SSD and what unRAID does for the sleep. I believe unRAID will keep sending the spin down commands to the drive anyways. The big question if if Simplefeatures will still poll the drive to see if it's spun down or if Simplefeatures was written to recognize the SSD. I guess another question would be what response does a SSD give to the spun down polling. The Simplefeatures questions might be better posted in the Simplefeatures thread.

First Of All Thank You For The Posts. I'll Post This Evening the question About Simple Features In The Subtopic.

But If I Understand Correctly. If I Set The limit Right On The Cachedrive. There Isn't Any chanceThat Transfer Fails Using  Microsoft Explorer . ( Even If The Total Amount OF Files Transfering To The Raid Is Larger As The Cachedrive)

First Of All Thank You For The Posts. I'll Post This Evening the question About Simple Features In The Subtopic.

But If I Understand Correctly. If I Set The limit Right On The Cachedrive. There Isn't Any chanceThat Transfer Fails Using  Microsoft Explorer . ( Even If The Total Amount OF Files Transfering To The Raid Is Larger As The Cachedrive)

Correct.

 

Once the free space on the cache drive goes below the value specified as a minimum then all new files are written directly to the main disks bypassing the cache.  The key item is picking a value for the minimum free space that will allow all files created before the minimum was reached to finish being written.  What is a sensible value therefore depends on the maximum size of files you are likely to be writing, and the number that are being written in parallel.  As an example I find that a value of 25GB works fine for me on my 250GB cache drive.