response 219 of 334:

Dec 4 22:44 UTC 2010

Here's something that looks interesting, if we were thinking of doing
some sort of training or providing tutorials:

  http://moodle.org/

It also has forum facilities in addition to other facilities for
education.  It's free software, and there is commercial support
available.

Of course, we probably don't need anything quite so complex to provide
a tutorial.  And things like slideshows can be produced other ways and
presented in other ways.

Just something to think about if we want to add some educational
materials to Grex, such as Unix skills or programming languages
instruction.

response 221 of 334:

Dec 5 03:54 UTC 2010

Thank you, Dan!

response 223 of 334:

Dec 6 02:19 UTC 2010

that's neat!

response 225 of 334:

Dec 9 04:33 UTC 2010

Okay, so several of us were talking about getting users access to
MySQL and PostgreSQL, both of which are installed here on Grex.  I had
mentioned that the Board discussed such access months back and the
comment I heard from staff members was that any such usage needed to
be part of the quota system, potenially necessitating a complex setup
to make sure the size of db files got counted under the right quotas.
One way to implement this sort of setup is to run multiple db servers,
each pointing to a db in a single user's home directory.  It sounds
complicated and potentially resource intensive.

Dan asked who said that, and at this point I don't recall, only that a
couple staff appeared to agree that was the way to go. I never heard
anything more about it after that.

Personally, I think it would probably work just fine if we had one
central db and allowed users to have accounts on that and to create
tables there under their user ids.  That would certainly make the setup
much easier.

As to the potential for abuse, I don't see it as any different from any
other application that uses disk space.  It's something to manage.  And
if we made it by request and for validated users, we'd in theory know
who was causing issues, if any occurred.  And probably we'd have less
abuse type of issues in a requested service, as well.  There are no
guarantees, but I'm fairly tired of seeing the potential threat of abuse
holding the rest of the users back from getting the apps they'd like.
So, why don't we try this and see how it goes?

I think it would be a wonderful situation to be in where we outgrow
our current computer due to more people using the system in more ways,
rather than watch the current system die of old age.

response 227 of 334:

Dec 9 18:18 UTC 2010

CGI can be given without too many complications. For MySQL, how about 
we create a separate partition of 1GB and stick everything on that 
(it's automatically quota limited to whatever the mysql-user has access 
to which should be 1GB and mysql-homedir). We could create a bunch of 
test mysql-accounts/databases for people to experiment with.. that way 
we could: 
1. allot something really quick if a newuser wants it.
2. we could start advertising it as a service.

so if a newuser arrives, he can start work straight away on a 
pre-created account. By the time his script his ready, we'll prolly 
have come to some decision on how to handle MySQL properly (in terms of 
automated scripts to create db with a "proper" name, and some kind of 
disk quota measuring mechanism and validation/whitelist)

response 229 of 334:

Dec 9 18:27 UTC 2010

more importantly, what Sindi pointed out, we need a duplicate rootFS 
with suitable network-config! That's an absolute priority.. if the 
server goes down, someone in 'provide' just resets the box and we boot 
up via the 2nd FS so staff can login and fix FS1. Why didn't we go with 
something like this earlier on.. any idea?? 

basically it's a normal bsd install on hda1 and dd if=/dev/hda1 
of=/dev/hda2, and then suitable grub(or whatever bootloader entries) 
entries for both hda1 and hda2..

response 231 of 334:

Dec 9 21:15 UTC 2010

Or perhaps write a stored procedure do it instead.

response 233 of 334:

Dec 10 03:11 UTC 2010

Seems this is a popular problem to solve:
http://www.cyberciti.biz/tips/linux-unix-setting-up-mysql-database-quotas.h
tml

response 235 of 334:

Dec 10 04:51 UTC 2010

#!/usr/local/bin/bash
#
# Assumes each user has 1 database, named the same as their username.

MYSQLUSER="root"                            # MySQL username
MYSQLPASS="changetherootpasswordyo"         # MySQL password
MYSQLHOST="localhost"                       # MySQL hostname or IP
EXCLUDEDB="test mysql information_schema"   # Databases to be excluded

DBQUOTA=1                                   # Database quota in MB

MYSQL="$(which mysql)"
DBS="$($MYSQL -u $MYSQLUSER -h $MYSQLHOST -p$MYSQLPASS -Bse 'show 
databases')"

for DB in $DBS
do
   if [ "$EXCLUDEDB" != "" ];
   then
      for i in $EXCLUDEDB
      do
         [ "$DB" == "$i" ] && ( continue 2; )
      done
   fi

   DBSIZE=$($MYSQL -u $MYSQLUSER -h $MYSQLHOST -p$MYSQLPASS -Bse 'SELECT 
sum(data_length+index_length)/1024/1024 FROM information_schema.TABLES 
WHERE table_schema=\"$DB\" GROUP BY table_schema')

   if [ $DBSIZE > $DBQUOTA ];
   then
      $MYSQL -u $MYSQLUSER -h $MYSQLHOST -p$MYSQLPASS -Be 'REVOKE 
INSERT, CREATE ON $DB FROM \'$DB\'@'localhost'
   fi
done

response 237 of 334:

Dec 10 04:58 UTC 2010

Does that process look like it could be automated safely along with
account setup in MySQL?  I assume each user needs to have their own
account set up, so any tables they create would remain separate from
other users' tables.  Since each user gets a link back to the main MySQL
db, the user should be able to add tables to their own acccount without
a problem and the quota system will control how much data they can save.
Is that your understanding?

Anyway, this is what was discussed in a prior Board meeting in terms of
keeping a quota for the DB files in addition to the regular data under a
user's home directory.

I assume postgreSQL could be set up in a similar fashion.

response 239 of 334:

Dec 10 12:13 UTC 2010

resp:237 I don't think it would be such a great idea to symlink from 
the sqlarea into the userHomeDir.. what if the userdeletes his dbDir 
and creates another symlink? There's a whole can of worms we are 
opening up.. i think.. the moment you have a system process writing to 
a user area. I'm not saying it's a bad idea.. it's a nice solution 
because it looks cleaner..