2010-09-16

Ohio LinuxFest 2010

Last weekend (Sept. 10th - 11th) was Ohio LinuxFest 2010 - and it was the biggest one yet.  The growth each year of this conference is impressive;  both in attendees and vendors.  While the website is persistently void of detailed information[1] this is a great conference for users of Open Source software and I recommend everyone attend if at all possible.  While once a Saturday only conference it seems to have expanded, without much fanfare, to include Friday.  This year there was a free all-day training session by Zenoss on Friday that I would have desperately loved to attend but was announced too late to make that possible.  Next year I hope to be there for the Friday sessions.  We (I and a sys-admin from Kalamazoo) did make if for the pre-party however - which is also something not-to-miss;  it is a great opportunity to hobnob with other users, including some well-known luminaries.  The nearly unlimited drink-tickets makes that even more entertaining.

Saturday's conference track began with Stormy Peters' excellent keynote on "Who is stealing your desktop?" about the dangers of cloud computing and the, almost stealth, proprietary services that so many users have come to rely on.  It raises the question if Open Source "won" only to then give up and accept yet another hegemony of corporations.  This same sentiment was echoed in Phil Robb's [of HP] talk "Irrelevance of the desktop".

Then it was on to regular part of the conference.  This is where I have one serious gripe about OLF: the topic selection.  It seems so "LINUX Journal".  They aren't "bad" topics, but it seems a lot of sessions are spent on promotional, evangelistic, or quite esoteric fare.  I'm generally opposed to almost all forms of "evangelism" so I'll admit I'm biased - but talking about promoting Open Source or how Open Source is better or the history of Open Source at an Open Source conference... doesn't this seem like preaching-to-the-choir and self-congratulation?  The very first year I went to OLF I learned about what was new with PostgreSQL [from a PostgreSQL developer!], about Apache mod_rewrite, about SMTP grey listing, etc... really solid detailed stuff.  I'd sit down and the presenter would dive right in.  I still have the notes from that conference and I still use all that information in my daily job.  That is lacking in recent OLF years where I come away with only a couple of actually useful bits of information.  I still go because it is simply fun and the feel you get for the direction of certain projects and vendors is valuable in its own way.

Probably the best presentation was David Nalley's (ke4qqq) talk on SELinux.  SE has always seemed like a black box - a black box to promptly be disabled!  Only a few sentences into his talk and David had knocked the sides of that box.  Straight-to-the-point and beautiful.  Over time I will now proceed to re-enable SELinux at least on my DMZ hosts.  There was some overlap between this an Deral Heiland's "And Now They Own You" - which could also have been named: "PEOPLE!  FIREWALL EGRESS TOO!".

Oh, and Asterisk 1.8 will support IPv6!  Another side-effect of OLF is to install a deep sense of Asterisk envy in those saddled with lousy / proprietary phone systems.  CalDAV integration with the PBX... really... why didn't someone thing of that feature before?  How simply spectacular.  Oh, wait,  I have Nortel phone systems... @*(&$&*(@*(& &*(@^$&*@^* @&^@$@!

[1] Even now the schedule page lists the "Pre-Party" details "TBD" (to-be determined).  Fortunately a quick Twitter search discovered where it was.

XFS & Inodes

There was an interesting thread on the opensuse list this week;  and regular readers will note how rare an event that is [even if you filter out the KDE-users-who-hate-KDE and the IPv6-is-irrelevant-malcontents].  It had to do with the XFS filesystem and inodes.  At least it was interesting to me as I recall facing the exact same problem several years ago.  While, unlike traditional UNIX filesystems, XFS doesn't suffer from the boring old issue of "inode exhaustion" it does have inode limits - based on a percentage of the filesystem size.
linux-yu4c:~ # xfs_info /mnt
meta-data=/dev/sdb1              isize=256    agcount=4, agsize=15262188 blks
         =                       sectsz=512   attr=2
data     =                       bsize=4096   blocks=61048752, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=29808, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=0
realtime =none                   extsz=4096   blocks=0, rtextents=0
The key is that "imaxpct" value. In this example inode's are limited to 25% of the filesystems capacity. That is a lot of inodes! But some tools and distributions may default that percentage to some much lower value - like 5% or 10% (for what reason I don't know).  This value can be determined at filesystem creation time using the "-i maxpct=nn" option or adjusted later using the xfs_growfs command's "-m nn" command.  So if you have an XFS filesystem with available capacity that is telling you it is full: check your "imaxpct" value