High water starting at 2TB for 16TB drives?

[Hastor]

Using 6.9.2. I'm setting up my first share. Pretty much everything is default. I'm using High Water allocation, and Split Level is set to automatically split directories as required, which sounds like it just goes by what the allocation method wants to do. I understand that High Water starts at 50% of the largest drive, then 50% of that and so on.

 

Currently I have, for data drives, 1x16TB and 2x10TB, along with two 16TB for dual parity. I'd expect this to fill each drive to 8TB before moving on to the next. However, it seems to move to the next after hitting the 2TB mark. I actually prefer this, but wondered why it is happening this way, and if it is something I can further adjust. I did think 8TB was a bit much considering I'd like to add some smaller drives as well, which would hit the min free space before hitting an 8TB high water mark.

 

I'm not sure if it would matter, but I started with the single 16TB drive and filled it to 11.3TB, then I added the parity drives and built the parity data. After that, I added the two 10TB ones. So the 16TB has 11.3 TB on it, and it started writing to one of the 10TB as expected, but changed to the other 10TB after hitting 2TB on the first. My guess is that it would have kicked in at 2TB even if all the drives were empty to start with.

Edited May 6, 2021 by Hastor

[Squid]

Include / Excluded disks override highwater, along with split levels on the shares.  (Assuming the min free space you set isn't actually 14TB)

[Hastor]

2 minutes ago, Squid said:

Include / Excluded disks override highwater, along with split levels on the shares.  (Assuming the min free space you set isn't actually 14TB)

It's the only share I've made and includes all disks, excludes none. So shouldn't high water start at 8TB? Or am I missing something else?

Min free space is just at 300GB for now, it will be a while before I have to worry about that and will likely change it.

Edited May 6, 2021 by Hastor

[Squid]

50% is exactly how highwater works  You can always post your diagnostics

[Hastor]

I've attached my diagnostic file. I'm a bit new here, so let me know if that's what you'd need. I'm using a pretty vanilla install and haven't really changed anything beyond the defaults. I am currently using the "turbo write" as they call it, since I'm adding a lot of initial data, but am adding a cache and using the standard write method once I get my data migrated.

megachurch-diagnostics-20210505-2341.zip

[Squid]

Disk 1 has 4.3 TB available on it.

Disk 2 7.3 TB, Disk 3 8.1 TB ( but without really diving into it, this might be a TiB vs TB thing)

 

So it looks like it's working fine.  Files are probably going to disk 1 right now.

[Hastor]

Just now, Squid said:

Disk 1 has 4.3 TB available on it.

Disk 2 7.3 TB, Disk 3 8.1 TB ( but without really diving into it, this might be a TiB vs TB thing)

 

So it looks like it's working fine.  Files are probably going to disk 1 right now.

Oh, so I completely misunderstood and had it backwards lol. I was thinking it would FILL each drive to 8TB, like the data would fill until it hit a 'high water mark' of 8TB and then move to another drive. Reading more carefully, I see that. Too much time around the lake and working on seawalls, I think of a high water mark as something being filled to that line. It however is filling until one has less than 8TB of free space, and then moving on. Makes a lot more sense.

Sorry for being a bonehead on this one, my future questions won't be like this!

[Hastor]

@Squid Thanks for your help on this. Since it isn't of much use to anyone that reads a bit more carefully, I'll delete it in a sec, but wanted to say thanks!

[Squid]

4 minutes ago, Hastor said:

@Squid Thanks for your help on this. Since it isn't of much use to anyone that reads a bit more carefully, I'll delete it in a sec, but wanted to say thanks!

We don't generally delete threads around here, but leave them for other users to see.  If you can misunderstand something, so can anyone else..

[Hastor]

Well dang, I just deleted it before seeing your message. It looks like it is still here now though. I'll keep that in mind for the future.