demonmaestro Posted June 14, 2015 Share Posted June 14, 2015 Is it possible to use a flash drive as a cache? Note: I did do a search and had found this question was asked back in 2012. It has been a few years since then. Link to comment
CHBMB Posted June 14, 2015 Share Posted June 14, 2015 I don't think so as flash is USB and I'm not sure you can mount USB devices as part of your array. With the Unassigned Devices plugin you could mount a flash drive to use for whatever you want, but the fancy jiggery pokery of moving to array after caching array writes wouldn't work. Plus I don't really thing Flash memory is suited to this purpose. Link to comment
Encino Stan Posted June 15, 2015 Share Posted June 15, 2015 As a side question. I read in the requirements that the boot device needs to be 512MB or larger , and I saw that the preconfigured USB Flash drive is a 16GB USB3.0 and the photo appears to be a SanDisk Ultra Fit. The 32GB SanDisk Ultra Fit was just $4 more than the 16GB, so I bought the 32GB. Is there some use for all that extra space? How much space is needed for the OS? Could the drive be partitioned into two 16GB devices (or a 2GB UNRAID and 30GB something else)? Link to comment
RobJ Posted June 15, 2015 Share Posted June 15, 2015 As a side question. I read in the requirements that the boot device needs to be 512MB or larger , and I saw that the preconfigured USB Flash drive is a 16GB USB3.0 and the photo appears to be a SanDisk Ultra Fit. The 32GB SanDisk Ultra Fit was just $4 more than the 16GB, so I bought the 32GB. Is there some use for all that extra space? How much space is needed for the OS? Could the drive be partitioned into two 16GB devices (or a 2GB UNRAID and 30GB something else)? Many of us still boot with a 1GB flash, with over half unused. You can try reserving a first partition of 1GB for unRAID, and 15GB for anything else you want, but remember that booting flash drives is finicky. Test it first, before putting it into production. Also, the unRAID flash drive has to stay inserted, which makes it somewhat unusable for temporary transfer space. And most tools (like SNAP and the Unassigned Devices plugins) do not support a second partition (at least, not yet, if ever). Link to comment
JonathanM Posted June 15, 2015 Share Posted June 15, 2015 Is there some use for all that extra space?To increase the useable lifespan? https://en.wikipedia.org/wiki/Wear_leveling Link to comment
Encino Stan Posted June 15, 2015 Share Posted June 15, 2015 Is there some use for all that extra space?To increase the useable lifespan? https://en.wikipedia.org/wiki/Wear_leveling Interesting idea, but doesn't look like FAT32 does it. Link to comment
JonathanM Posted June 15, 2015 Share Posted June 15, 2015 Is there some use for all that extra space?To increase the useable lifespan? https://en.wikipedia.org/wiki/Wear_leveling Interesting idea, but doesn't look like FAT32 does it. Wear leveling is done at the chip controller level for most if not all modern USB and SSD drives. The file system doesn't even know it's happening, but new writes are sent to fresh physical locations even if the FS tells it to overwrite the data. Long boring technical details aside, that's the short and sweet version of why SSD and flash memory is very hard to securely erase. Link to comment
korpo53 Posted June 17, 2015 Share Posted June 17, 2015 Is it possible to use a flash drive as a cache? Note: I did do a search and had found this question was asked back in 2012. It has been a few years since then. Probably. But it's also probably a very bad idea unless you have one of those fancy USB drives with an SSD controller built in. Standard USB drives are pretty dumb and not very good about wear leveling, whereas SSD controllers are very good at it. Also, even if you had a 16G or 32G flash drive, that's pretty small as far as cache drives go... considering you can get 128G real SSDs for like $50 these days. Link to comment
trurl Posted June 17, 2015 Share Posted June 17, 2015 Is it possible to use a flash drive as a cache? Note: I did do a search and had found this question was asked back in 2012. It has been a few years since then. Probably. But it's also probably a very bad idea unless you have one of those fancy USB drives with an SSD controller built in. Standard USB drives are pretty dumb and not very good about wear leveling, whereas SSD controllers are very good at it. Also, even if you had a 16G or 32G flash drive, that's pretty small as far as cache drives go... considering you can get 128G real SSDs for like $50 these days. Not probably. Not possible. Link to comment
Unqualified Spectator Posted July 9, 2015 Share Posted July 9, 2015 If you setup another flash device in Unassigned Devices, with the intention of just making a data drive SPECIFICALLY for Serviio or Plex (somewhere to stash the scraped metadata) - would it work? The reason I ask is that I would like to try Serviio - my system mobo is very small and I don't have a spare sata port and no expansion slots. (Yes, I know I need to upgrade my mobo - kid in college vs. money for toyz - kid wins.) I installed the Serviio plugin and it complains about not surviving a reboot because I have no cache - So I am looking for a workaround. I have a pretty cool 128GB USB device I would like to try to use as a proof of concept. I think it might be like a "slow" SSD. The problem is that it is a USB 3.0 device and I've found that it sometimes just won't play nice with USB 2.0 - it is a Monster Digital 128Gb External SSD. So, if it is recognized by Unassigned Devices, it might work - no spin up, just USB channel "lag". I wish I had bought 2-3 of these when I did - SAMS Club was practically giving them away at $29 a few months back. Update - I found a thread from May where this was discussed - seems to be a bad idea and itimpi stated that you cannot assign flash devices as disks. http://lime-technology.com/forum/index.php?topic=39755.msg372096#msg372096 Bummer. Link to comment
archedraft Posted July 9, 2015 Share Posted July 9, 2015 Assuming the Unassigned Devices plugin will allow you to mount a flash drive then yes it should be no problem to store the config files on the flash drive. If that doesn't work (and your using unRAID 6) you create a share that only stores data on disk1 and store your config files there. The only downside to that is disk1 will always remain spun up if Serviio is active. Link to comment
Unqualified Spectator Posted July 14, 2015 Share Posted July 14, 2015 Thanks, Archedraft. I find myself in quite a dilemma... I need to upgrade my hardware...what I want is rather expensive ($650+) - so, for reasons already mentioned, that ain't happening. My hardware is so pathetic that there is practically no benefit for me to upgrade until I can replace my mobo, memory and CPU. If I purchased my license, It would only gain me 1 additional SATA port. I want to acquire to a PLUS license since I think that would be the largest size my array would grow to for at least 5 years. Buying the Basic license is a waste of money since I know I will outgrow that almost immediately. (I could install my new 6Tb parity drive and try the UD Cache but then I am again - outta everything.) It's really hard to decide who's on first. So, I am searching for a cheaper hardware package that will get me 5 years more so I can proceed. As it is, I can't even try the UD plugin since I don't have any drives left in my license. I think using UD to add the Monster Digital or a flash drive as a "outside the array" storage for all the Serviio metadata would be a fun project and, if it worked, give a MUCH faster response than my old WD Greens. (I've been waiting 30-40 seconds for them to spin up for a couple years now - every time I spin up the array to watch some Trek for bedtime!) (Sidenote: I did install UD, but as expected, it did not detect my device.) Just pathetic. :'( Gotta find a way to make this happen. Link to comment
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