I need a file server for my HTPC as I've now more than 20 2TB HDDs full of media files. Since I can't put the file server at another room, and I want to save on energy, I want all those HDDs in spin-down mode except actual media playback or file read/write.

 

That means I need "directory caching". It seems most if not all file server systems do not do "directory caching". And I don't want to wake all HDDs by simply browsing my media file list.

 

So I find this, and it seems what I needed:

http://lime-technology.com/wiki/index.php?title=Improving_unRAID_Performance#Keep_directory_entries_cached

 

But then the talk seems on the Linux filesystem level. If I setup this I will share the HDDs to my Windows 7 HTPC using CIFS/Samba. In Windows Explorer, besides basic file attribute, Windows often also want to look for many more media file metadata, such as thumbnail, ID3 tag info, preview image etc. Some helper program may want to look into a zip/rar file just by an encounter in the file browser.

 

Does this holy "directory caching" function really work in a Windows client setup?

 

Another question is that by using a black-box file server, the system will decide which physical HDD to hold which file/folder. I have many BD ripped in BDMV folder. The movie is composted in many small TS files. If those TS files are distributed to different physical HDDs, then in the middle of a movie it may need to wait for a HDD to spin-up to continue. Or the system is smart enough to place a BDMV folder always on a single HDD?

 

Thanks in advance.

 

PS: from reading topics on "directory caching", I understand the function is limited by RAM, but RAM is very cheap these day. I can use 16G or even 32G RAM if that is needed for a complete "directory caching" functioning...

Directory caching using the tool cache_dirs will work for most people.

 

People with hundreds of thousands of files may not see the benefit as there is a fixed hash table that holds only so many entries.

 

You can put more ram in your system, however the table is in low memory, and it seems as if it cannot exceed low memory.

 

As far as caching filenames and files that do not exist. It will work and windows will get the benefit of the cached directory data.

 

Most people receive a benefit from cache_dirs.

 

As far as keeping files together, that's what split level is for when defining user shares. You tell unRAID where to divide a directory between multiple hard drives. You can also write the files to a disk share thus having control on where you stage files. (This is how I do it).