What to add for another HDD, and why is it Caching during streaming now.

[Ron]

Question 1: I am currently running unRAID Plus Server V6.0-beta5a. I am running (4) Hitachi 4TB 5200 HDDs (one is parity), and want to add another drive as I am down to about 1TB available... I am wondering if i should go with a SSD for a swap drive, and another 4TB or not. Will it speed up my server any?

 

Question 2: Everything was fine until I went to the V6.0-beta5a when I took my whole system down to move it to our new location. Then I started having a problem where while streaming a movie it will pause for a few seconds, and I believe it says loading cache. I never had this problem in the past, and now it happens once or twice during a movie. I am using OpenElecXBMC as a media server (i3NUC), and I have a Atom UnRaid server.

 

Is there a setting that needs to be changed in the new version that wasn't in the older one? Is this a bug?

[Ron]

I figured out the caching bit... Apparently the drives were set to spin down after 1 hour. I changed it to 4 hours and so far no caching.

 

 

Will changing my parity drive to a Hybrid or a 7200rpm drive speed up my transfers?

[garycase]

The reason you were having the delays was that your movies are apparently stored in DVD folder structures ... so there are multiple VOB files ... and you don't have the split level set to ensure individual movies are always saved on the same disk.    That's okay ... but as you noted, it means there will be a delay whenever a movie that's being played back needs to access the next VOB segment and it's on a disk that's not spinning.  Changing your spindown time to 2 hours would be fine for almost all movies (even those slightly longer than 2 hours are likely already playing the last VOB by the 2 hour point).

 

Changing your parity drive to a faster drive will make no difference in playback speeds.    It may marginally speed up write speeds -- but only when you have multiple writes happening simultaneously (e.g. if more than one system is writing data to UnRAID at the same time).

 

[Ron]

So I should have set up my movies to be on a single drive instead of allowing them to be on all 4 drives? I guess it is a little late to change that now. Thanks for the info. I guess I will just get another 4TB Hitachi 5400 rpm drive then.

[garycase]

Many movies are stored in single-file "containers" (e.g. mkv's), so once you start playing it, there's no need to access additional files .... so there wouldn't be any need to access other disks.    But if movies are stored in DVD folder structures [.IFO and .VOB's] then as the movie plays it accesses VTS_01_1.VOB, then VTS_01_2.VOB, then VTS_01_3.VOB, etc. => so if these are spread across different disks, then there will be a delay if the needed file is on a disk that isn't currently spinning.

 

How likely it is that you'll have movies that span different disks is a function of your split level and allocation settings.    If your allocation setting is one that causes frequent changes in the disk being written to (e.g. "most free"), then it's fairly likely you'll have a lot of movies that span multiple disks.    If the allocation level only rarely changes disks (e.g. "fill-up") then you'll have very few that have the issue.    Same is true for "high water", which changes disks more than "fill-up" but far less than "most free".

 

You can also use "Split level" to force movies to stay together.  For example, if your movies are all stored in a "DVDs" share, then using split level 2 for that share will force UnRAID to write all of the files associated with a single movie on the same disk.

 

Note that you can change those settings now and it will keep all future movies together, but won't have any impact on everything that's already on the system.  For those, you'll simply need to either live with the occasional delays; or be sure all disks are spinning when you're playing a movie [using a spin-down time of 2 hours will, as I noted earlier, work fine as long as you spinup all disks before starting the movie]

 

 

[garycase]

Note:  There IS a slightly "out of the box" way you can force this problem to never happen while at the same time leaving your spindown times set to a modest value (30 min or an hour).

 

(1)  Change the split level for your shares, so this problem wont' happen with future movies you copy to the array.

 

(2)  Enable "Spin-Up Groups" on the Settings page (for Disk settings); and put your 3 current data drives in a group.    This tells UnRAID that whenever one of those disks is spun up, it should spin up all of the drives in the group -- and it should not spin down any of them unless all 3 have been idle for the spin-down time.

 

This will "fix" the issue for those drives that have movies split across them; yet won't requires that you keep future drives unnecessarily spun up as you add more movies to the system ... and will let those 3 drives spin down when you're playing movies from your other drives in the future 

[Ron]

Thanks.

All of my movies are .mkv files. I have my movie folder setup as:

High water

Min free space=0

split level is blank

included discs= disc 1, disc 2, disc 3

share empty=no

 

 

I have enable spin up groups=yes... How do I put the 3 current drives into a group? All my drives are solid green LEDs... Would that mean they are already grouped?

[garycase]

If your movies are all .mkv files you shouldn't have the pause issue you noted -- once the disk with the .mkv is spinning, the movie should play fine without any requirement to spin up any other disks.

 

The cache message you're getting is likely from your media player ... which may not be buffering enough data from your server to keep playing while it loads more.    This may also be related to your network ... have you changed your network topology since your move?

 

[Ron]

The only thing that might have changed on my network is... There are 2 Lan ports on the UnRaid mb... I tried one after relocating everything and it didn't work (might have never worked as I never tried both ports). I then tried the other port and it worked. I use a Cisco Gigabit 24 port Business switch which has not had any settings changed since initial install. I will look some more on my OpenElecXBMC Media Server to see if there are any settings for cache... Strange thing is since I changed the setting for spin down in UnRaid the problem has not happened again.