July 21, 201411 yr I have a spare 256 GB SSD I want to add to my new UNRAID box. I have gathered the following from reading the forums: 1. I can install an SSD outside of the array and put my applications on it (Plex, Sabnzb, Airvideo, Owncloud, Crashplan) Why would I put my SSD outside of the array vs. using it as a Cache drive? Jumperman has a guide to mounting ext4 SSD outside of the array. Should I now use BTRFS instead of EXT4? (I am on the latest beta) 2. If I understand correctly, I should use a fast spinner as a Cache drive and put my apps on an SSD outside of the array? Is that the best approach? I have never allowed my UNRAID box to go into sleep mode... which would be great. What is the best approach to both add an SSD and get to use sleep mode when the server is idle?
July 21, 201411 yr You can also put your apps on the cache drive if you want to use it as a cache. Just depends on whether or not you want to share the drive. I'd definitely use BTRFS now that UnRAID is finally going to support it.
July 21, 201411 yr Author But is there a disadvantage to having an SSD Cache with apps on it? I currently have a spinner cache with apps on it. Sent from my SM-N900V using Xparent BlueTapatalk 2
July 21, 201411 yr But is there a disadvantage to having an SSD Cache with apps on it? I currently have a spinner cache with apps on it. Sent from my SM-N900V using Xparent BlueTapatalk 2 Really, the only disadvantage is the smaller size of the SSD.
July 21, 201411 yr Author Ok. So having an SSD as a Cache drive with apps on it will not prevent the server from going to sleep when there is no activity for a while? I thought I read something like that somewhere around here.
July 21, 201411 yr Ok. So having an SSD as a Cache drive with apps on it will not prevent the server from going to sleep when there is no activity for a while? I thought I read something like that somewhere around here. I know nothing about this thing you call sleep. Mine is a server, it spins 24/7.
July 21, 201411 yr Author "What is this sleep you speak of?" Seriously. Since Netflix and HuluPlus my family spends a lot of time during the day not using the server. There are days at a time when the apps are mostly idle. Isnt this the type of scenario where the server would go to sleep?
July 21, 201411 yr "What is this sleep you speak of?" Seriously. Since Netflix and HuluPlus my family spends a lot of time during the day not using the server. There are days at a time when the apps are mostly idle. Isnt this the type of scenario where the server would go to sleep? Drives - Yes. I have spindown set to 1 hour. Server I leave running 24x7.
July 21, 201411 yr Author Ok. So just picked up a second SSD. I'll use one for Apps and one for Cache. Am I correct to assume that if I format them both BTFRS that I can install docker on the app drive and not the cache drive?
July 21, 201411 yr Ok. So just picked up a second SSD. I'll use one for Apps and one for Cache. Am I correct to assume that if I format them both BTFRS that I can install docker on the app drive and not the cache drive? Yes, you can choose your path for where your containers will go.
July 28, 201411 yr Author Any reason why the SSD MX100 would not be recognized by UNRAID? http://www.amazon.com/Crucial-MX100-adapter-Internal-CT256MX100SSD1/dp/B00KFAGCWK/ref=sr_1_1?ie=UTF8&qid=1406578103&sr=8-1&keywords=mx100
July 28, 201411 yr Any reason why the SSD MX100 would not be recognized by UNRAID? http://www.amazon.com/Crucial-MX100-adapter-Internal-CT256MX100SSD1/dp/B00KFAGCWK/ref=sr_1_1?ie=UTF8&qid=1406578103&sr=8-1&keywords=mx100 That should work just fine.
July 28, 201411 yr Any reason why the SSD MX100 would not be recognized by UNRAID? http://www.amazon.com/Crucial-MX100-adapter-Internal-CT256MX100SSD1/dp/B00KFAGCWK/ref=sr_1_1?ie=UTF8&qid=1406578103&sr=8-1&keywords=mx100 No reason it shouldnt. I was thinking about ordering two 512MB MX100's for my unRAID. I will wait to hear if you got yours working or not.
July 28, 201411 yr Maybe he would like to copy 10 pictures at a time and run the mover and repeat... You never know!
July 28, 201411 yr The two reasons for not using an SSD as your cache are: 1) It might be too small, even at 256GB, to house all your apps and their associated databases (like a huge plex db) AND have enough room left over to serve as cache for a full day's worth of transfer. With my small 60GB SSD, large plex database, and regular 30GB daily transfers I can't use my SSD as a cache. Your situation may be different, but I've heard of people with HUGE libraries having HUGE databases due to the indexing feature in plex. 2) reiserFS does not support TRIM (via DISCARD mount parameter) at all for your SSD. With BTRFS you are able to run fstrim manually however for now you are not able to turn on DISCARD to do it automatically. There are debates about the turning on DISCARD and its impact on performance so there is that. Finally, if you have one of the SSD's with very good offline/non-trim driven garbage collection then this whole bullet is not a big deal.
July 28, 201411 yr Author I have 2 SSDs. Both 256gb. The plan is to use one for cache and one for apps. I will format both with BTFRS, which I believe supports TRIM. The mx100 is in an Icydock, so I'll open up tonight and try again. I'll report back.
July 29, 201411 yr 256GB is PLENTY for a cache ... that's far more than most folks are likely to transfer in a day !!
July 29, 201411 yr Plenty indeed knowing that he has another to do app and app-data duty. If I were so lucky ... or motivated to change my money priorities from fancy food to fancy drives Right now BTRFS in unraid does not support enabling discard when mounted; Tom says it will in the next release. In the mean time, you will have to run fstrim periodically. That is not too problematic as you can run it as a cron job, but it is what it is. If you did your app drive in ext4 then you could mount it with discard enabled. But of course then you would lose qcow if that is important for your non-cache drive.
July 29, 201411 yr I happen to think that an SSD is a great choice for storing Docker containers and VMs. It will have a profound impact on performance. They are also an excellent place for large databases that support apps that run our your sever (like Plex, although Plex's database can get quite large). But I think they are a crappy choice for a cache disk. First of all the speed of copying data to the cache is network limited, meaning you are only marginally benefiting from the SSDs high speed, and secondly, SSDs have a limited number of writes. And each time you copy a large file to the cache you are using it up. And for what? A little faster copy to the array? I therefore suggest people invest in an SSD, format it in BTRFS, and use it for containers (and appdata if you like, although I keep appdata on my cache), get a 7200 RPM spinner for the cache. The will dramatically reduce the writes to the SSD, give you great performance in your containers, and give you quite good performance if you want to cache writes to the array.
July 29, 201411 yr This seems to hint that BTRFS is not a great choice for VM images. https://btrfs.wiki.kernel.org/index.php/Gotchas I've only ever used ext4 outside an array to host apps and VM images so I wouldn't know for sure.
July 29, 201411 yr Author This seems to hint that BTRFS is not a great choice for VM images. https://btrfs.wiki.kernel.org/index.php/Gotchas I've only ever used ext4 outside an array to host apps and VM images so I wouldn't know for sure. Interesting! I think. I mean, I bet if I understood what the heck they were talking about I would think it was interesting Seriously. What part of that is concerning about using an SSD for a docker container?
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