09 December 2008, 15:57

Hello

 Have looked through forum and wiki and cannot find info on following - but apologies if we have missed it - please point us to the url in that case.

 We are impressed with Mahara and planning on implementing it in the new year.

Current thinking is:

Ubuntu server (current LTS version)

on a dedicated server with max RAM and 4 disks initially -

2 mirrored for OS Mahara and database

2 mirrored for file storage

We have 1700 students and 200 staff. If this takes off we anticipate a lifecycle of 5 years or maybe more though lots of unknowns in there.

So our intial question is how we configure the file store to allow for future expansion.

Probably start with 1TB storage for file store - giving average 500MB per user - not much for modern student who may include sound photos and video in their portfolio - especially if built up over 5 yrs+ (would probably set limit of 350MB as many would not use it all - thus giving spare available to the 'hungry' ones - to begin with)

Detailed technical knowledge of Linux filesystems is limited.

We would welcome advice on best way to set up the file store so we can expand it later without having to move existing files etc

 We are also interested in how existing sites are handling backup of user files - given potential sizes involved - or are you making users responsible?

Hope this makes sense.

TIA

09 December 2008, 20:44

Hi,

I think your estimate for how much file storage you will need is excessive. The vast majority of your users may never bother to store anything at all. 1TB should certainly be enough for you for quite a long time.

If you use LVM, you can put your filestorage on a separate LV, and grow that when you need more space. LVM is the best way to do this under linux. It means you can more disks and dynamically add them to the LV as your space needs increase.

At Catalyst, we handle backups using tape drives to record to tape, and send the tapes offsite for secure storage. It's unrealistic to make the users responsible for backing up their data, especially because Mahara doesn't provide a way to export all the user's data right now.

Hope that helps you

10 December 2008, 6:11

Hello and thanks for prompt response.

Our estimate is based on LAN usage which has run out mopre than once over recent years (even after increasgin disk capacity) as more muiltimedia work is undertaken, though I take your point on many users underutilisieng what is made available to them. I guess it is finding the optimum limit to place on the storage quota - maybe even lowe than the 350MB suggested, thus allowing more for the 'superusers' who seem to eat as much (and more)as they are given.

We will look into LVM - not something with which we are familiar, and maybe come back for any clarification if that is Ok.

That may also help with our understaning of backups.

Is the principle similar to Moodle - ie backup 3 things - script/website, database and file storage area?

I have seen staff and student guides to Mahara - are there any docs for system admins? (or are they in the download)

thanks

10 December 2008, 16:32

Yes the principle is similar to moodle - code, database and dataroot. The dataroot will by far take up the most space by the way.

There's no guides for sysadmins yet.. we need to write a whole bunch of documentation on the wiki but haven't quite got around to it yet . I see Andy has made a start on putting some user guide stuff up, though that's not complete yet.

10 December 2008, 17:56

OK - thanks for your help - I think that gives us some more to chew over as we try and plan the hardware and the implementation.

I was thinking we could share Mahara with an existing Moodle server (and upgrade the disks) but with 32bit OS and 4Gb RAM limit that may be optimistic. Are there calculations for Mahara as on the Moodle docs site for working out concurrent and browsing users against RAM etc

So another question pops up that may be an option - how about running Mahara as a VM? any likely problems that you can think of? (especially if accessed over https)

Off to Google LVM now ....

thanks again

10 December 2008, 18:39

32 bit OS shouldn't cause any issues, in fact in many ways it's better than 64bit when it comes to PHP webapps right now.

You could probably share the servers if you know how much load the server is under/how much ram/cpu are used by moodle. If you're not recording that data then you should start, because it allows you to make the right decision in cases like these.

Mahara has a somewhat smaller, but similar footprint to Moodle. It performs far less queries to generate the average page that Moodle does. RAM usage will be less, but probably not by too much.

Running in a VM almost always equals bad news for disk performance... Mahara and Moodle should sit side by side quite happily on the same server. 

11 December 2008, 17:13

Many thanks for your helpful and prompt advice.

It has helped us get a better picture of where we think we need to go.