How does OMV handle spin-up of multiple hard drives?

TOMillr · 22. Juni 2019

I'm curious how OMV handles spin-up an spin-down of connected hard-drives.

Let's say the OS/OMV is installed on an SSD, but most of the data is stored on traditional spinning hard drives. I'd like to have those drive go into standby/spin-down as often and long as possible.

When does OMV wake up those HDD? Only when a user accesses a file on the HDD? Or does it spin up the drive every time a user accesses a folder or the tree structure?

How about a case when there are multiple hard drives installed? Let's say a file is stored on drive B and the user would try to open that file. Does it only spin up drive B? Or drive B as well as drive A and every other drive connected to the system?

tkaiser · 22. Juni 2019

Zitat von TOMillr

I'm curious how OMV handles spin-up an spin-down of connected hard-drives.

OMV does nothing here since this all depends on what the Linux kernel does depending on how you configured your storage. With 3 drives and RAID5 all drives will spin up, with other attempts that keep each disk independent from each other this won't happen.

You need to provide a bit more details about your setup...

neurotone · 22. Juni 2019

With being on that subject tkaiser what would you recommend for someone that uses OMV for Plex and in-house file sharing? sharing example I have two 4 terabyte NAS Drives and one SSD for the OS I have left the SSD at default.
This is the current setting I have for both storage drives.

The drives are ext4 no raid however, raid is coming soon down the line it's just that damn money problem

TOMillr · 23. Juni 2019

Zitat von tkaiser

OMV does nothing here since this all depends on what the Linux kernel does depending on how you configured your storage.

And how about when you just browse through the file system (click from one folder to the next without actually accessing/opening any files)? How does Linux handle this?

Is the index of the file system stored on the system drive? Or does it always spin up the HDD you're browsing?

tkaiser · 23. Juni 2019

Zitat von TOMillr

Is the index of the file system stored on the system drive?

It's either cached in RAM (all the available RAM usually ends up being used for this sort of caches) or on the disk in question. Whether the disk spins up or not when you 'browse' the filesystem depends on too many factors to give any meaningful answer. I just had a quick look at an OMV5 test install:

Code

/dev/sdb1 /sharedfolders/ext4 ext4 rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group 0 0
/dev/sdb2 /sharedfolders/btrfs btrfs rw,noatime,nodiratime,compress=lzo,space_cache,subvolid=5,subvol=/btrfs 0 0

The ext4 formatted share has relatime set so accessing the filesystem contents will spin up the disk at lest once a day while the btrfs formatted share uses noatime,nodiratime so simple read accesses won't result in write activity. But that's just one of the many reasons why the disk needs to be accessed.

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