I ordered a 6TB drive today to add to my server. I was planning to use it as an unassigned drive to store some backups and Storj data (because the last one constantly spins up my drive and parity drives)

But an hour ago I started thinking, maybe it's better to add the 6TB HD to a new cache pool. If I select my Storj to prefer cache, it will never be moved to the array.

It seems better this way, no plugins needed, everything in the array. What do you guys think?

Using cache pools for permanently attached devices is what you should be doing.

I think most people select an SSD to operate as the Cache for various reasons.  May want to consider that.  Cache drive allows for faster operations of your important files and transfers, etc.  

43 minutes ago, Squid said:

Using cache pools for permanently attached devices is what you should be doing.

So if I understand correctly, if I plan to leave the drive permanently connected you would choose a cache pool. Even if I am not planning to use it as a real cache, just storage that does not need parity protection or speed.

 

I have a ssd cache pool in use but with the new cache pool feature I started thinking to use a second cache pool instead of the unassigned drives plugin.

 

Sorry if my explanation is not clear. I am not a native English speaker.

 

3 minutes ago, Croontje said:

So if I understand correctly, if I plan to leave the drive permanently connected you would choose a cache pool. Even if I am not planning to use it as a real cache, just storage that does not need parity protection or speed.

 

I have a ssd cache pool in use but with the new cache pool feature I started thinking to use a second cache pool instead of the unassigned drives plugin.

Yes, this is correct.  For permanently attached storage, cache pools are easier to deal with than Unassigned Devices and provide more flexibility.  UD still has several good uses especially with USB and other storage that is not always connected to the server.

 

If you are looking for speed, of course SSDs are better than HDDs as cache devices.  A cache "pool" can be a single device or multiple devices.

 

You can assign your HDD as a cache device and designate share(s) as cache only or cache prefer using this HDD cache "pool."  The only difference is what happens when the cache drive is full.  Prefer causes data to spill over to the array; cache only does not.

 

Nothing on this cache drive would be parity protected and therefore would write to the HDD at the speed of the drive.

Great!

 

Thanks a lot!

On 4/14/2021 at 6:31 AM, Hoopster said:

Yes, this is correct.  For permanently attached storage, cache pools are easier to deal with than Unassigned Devices and provide more flexibility.  UD still has several good uses especially with USB and other storage that is not always connected to the server.

 

Hi Hoopster, I know I'm late to the party, but I'm curious to know more about this. What are the specific advantages to having a spare HDD connected as a cache pool vs UD?

26 minutes ago, DavidNguyen said:

 

Hi Hoopster, I know I'm late to the party, but I'm curious to know more about this. What are the specific advantages to having a spare HDD connected as a cache pool vs UD?

The big difference is that pools can participate in User Shares (including the ability to act as a cache) whereas UD devices cannot.   UD devices are therefore more geared towards removable devices.

On 6/26/2022 at 1:11 PM, itimpi said:

The big difference is that pools can participate in User Shares (including the ability to act as a cache) whereas UD devices cannot.   UD devices are therefore more geared towards removable devices.

I know this is a very old thread - but let's say I want to use a USB drive solely as a TimeMachine backup disk. It would stay connected to the server. Would unassigned devices make more sense?