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USB Flash drive as cache - Printable Version

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USB Flash drive as cache - rjbathgate - 05-23-2015

Hi

I'm looking at improving the caching of my Raspberry Pi 2 for video streaming purposes.

Looking at this:

http://kodi.wiki/view/how-to:modify_the_video_cache

The option to set the buffer size (cachemembuffersize) as 0 results in the local hard drive being used for cache, opening up a massively larger amount of cache memory.

However, this would obviously increase wear and tear on the SD card.

So, I was wondering how to then use a USB flash drive for the cache.

Options I'm thinking are:

Boot to the Flash Drive (as per https://samhobbs.co.uk/2013/10/speed-up-your-pi-by-booting-to-a-usb-flash-drive)

or change the storage partition to a USB stick (as per http://openelec.tv/forum/124-raspberry-pi/70069-how-to-cache-to-usb-stick)

What I'm unsure on is... whether these two processes are actually same same but different. Or more to the point, which solution will actually result in the cache partition/location being now on the USB stick. No point setting it to boot from USB flash, or moving /storage/ to flash if it still uses it's internal SD card for the caching.

And, on that note, would there be anyway to determine the cache location, if I did set cachemembuffersize to 0 (thus using entire 'HDD')

Any advice, most appreciated.

Thanks in advance

Oh, and I know the USB stick might still suffer from using it as cache, but they are cheaper and very easy to duplicate so I have master img lying as backup :-)


USB Flash drive as cache - chewitt - 05-23-2015

I haven't read the articles, but since pi boards *cannot* boot from a USB (only an SD card) it must be the same process for moving /storage to USB.


USB Flash drive as cache - rjbathgate - 05-23-2015

Thanks for the quick reply.

Yes, it's not changing where it boots from:

Quote:The first thing to understand here is that a Raspberry Pi is currently incapable of booting without an SD card. So although you can move your filesystem to a USB, you still need to keep the SD card plugged in.

So, I guess my question is moving the filesystem to a USB stick (through either of those methods I guess) going to mean if I set cachemembuffersize = 0 will it use the /storage/ mount (now on USB) or will it continue to use some other mount of the SD card for cache?

In otherwords, where does it store cache when cachemembuffersize = 0 (i.e. on HDD) - because if it's somewhere within /storage/ then it'll confirm it'll go to the USB.

But without a way of knowing for sure, I could end up still using the SD for cache and wreaking it.

Thanks


USB Flash drive as cache - chewitt - 05-23-2015

it always uses /storage so will use the USB if that's where /storage has been moved to