[ale] ISCSI array on virtual machine

[Todor Fassl]

I need to setup a new file server on a virtual machine with an attached 
ISCSI array. Two things I am obsessing over -- 1. Which file system to 
use and 2. Partitioning scheme.

The ISCSI array is attached to a ubuntu 16.04 virtual machine. To tell 
you the truth, I don't even know how that is done. I do not manage the 
VMware cluster.  In fact, I think the Dell technitian actually ddid that 
for us. It looks like a normal 8T hard drive on /dev/sdb to the virtual 
machine. The ISCSI array is configured for RAID6 so from what I 
understand, all I have to do is choose a file system appropriate for my 
end user's needs. Even though the array looks like a single hard drive, 
I don't have to worry about software RAID or anyhthing like that.

Googling shows me no clear advantage to ext4, xfs, or zfs. I haven't 
been able to find a page that says any one of those is an obvious choice 
in my situation. I have about 150 end-users with nfs mounted home 
directories. We also have a handful of people using Windows so the file 
server will have samba installed. It's a pretty good mix of large files 
and small files since different users are doing drastically different 
things. There are users who never do anything but read email and browse 
the web and others doing fluid dynamic simulations on small supercomputers.

Secondthing I've been going back and forth on in my own mind is whether 
to do away with seperate partitions for faculty, staff, and grad 
students. My co-worker says that's probably an artifact of the days when 
partition sizes were limited. That was before my time here. The last 2 
times we rebuilt our file server, we just maintained the partitioning 
scheme and just made the sizes  times larger. But sometimes the faculty 
partition got filled up while there was still plenty of space left on 
the grad partition. Or it might be the other way around. If we munged 
them all together, that wouldn't happen. The only downside I see to 
doing that is that if the faculty partition gets hosed, the grad 
partition wouldn't be effected. But that seems like a pretty arbitrary 
choice. We could just assign users randomly to one partition or another. 
When you're setting up a NAS for use by a lot of users, is it considered 
best practice to split it up to limit the damage from a messed up file 
system? I mean, hopefully, that never happens anyway, right?

Right now, I've got it configured as one gigantic 8T ext4 partition. But 
we won't be going live with it until the end of May so I have plenty of 
time to completely rebuild it.

-- 
Todd
fassl.tod at gmail.com