August 2008 Archives

ZFS as a movie actor!

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Two mirrored volumes concatenated to give a 8TB storage pool. I logged 18 hours of block read/write activity and made a MPEG4-Movie out of it.

Green pixels summarize sector reads, red pixels sector writes. Each pixel represent the same number of consecutive storage blocks. The pixels are doubled in height because of the 4:2:0 color coding of MPEG4. Otherwise, a red pixel adjacent to a green one could not have been possible, as two lines are coded together with regard to color. It is a TV format, after all..

bg.gifAt half past eight, a backup job started, scanning many files. After 4 o'clock an expire run is started. And at 5 o'clock it is really "night" with user activity rebeginning at 6:30.

I used 640x480 pixel frames with 30 frames per second. Should be possible to watch on a NTSC TV :-)  Enjoy!

UFS and ZFS write patterns [Update]

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As a followup to this article, I used a zfs volume and an ufs volume with an application doing the same work on both partitions (replicated sql engines).

Click on the still frame to download the video (4 MB, ISO MPEG 4 format):


Obsolete things can be nice. They can be useful. These "cmusaslsecret"-Thingies are.
But let's start from the beginning. You may however start to play with them!

You are using Cyrus SASL for authentification purposes? Supposedly with the Cyrus IMAP server or Postfix (the two major applications using Cyrus SASL)? Then you'll know the problem: You may use saslauthd(8) to connect to an authentication database as Unix PAM or LDAP. Problem: You will only be able to use plaintext logins. Why?

If using saslauthd, the SASL-enabled server gets the password given by the user/client, and asks saslauthd whether it is correct or not.

Plaintext authentication can be sufficient when using it with SSL/TLS. In IMAP environments this may be a good solution if all mail clients can be configured in that way. With SMTP you will have a problem. Many Mailservers being able to initiate authenticated outgoing SMTP connections do not use SSL/TLS. Many of them want to use CRAM-MD5 as it is defined in many standard drafts.

The famous "Landessender Beromünster" will shut down on Dec 28th. The name of the little city "Beromünster" was known throughout Europe, as it was marked on many radio scales of the last decades. It's frequency is 531kHz (since 1978).

Beromünster started broadcasting on June 11th, 1931. After 77 years of operation, its end is near.

BeroNet BN2S0 with Asterisk and misdn

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Scenario: Two ISDN phones (a wireless DECT one and a comfortable one with cable) are to be connected to my Asterisk server which calls out via IAX2, SIP and ISDN.

As my mini case (which contains a VIA embedded board) does only have one PCI slot (via riser card), I chose the BN2S0 from BeroNet (Berlin).
It features a Cologne Chipset Design HFC chipset with 2 S0 (ISDN S/T) interfaces (click to enlarge):

IMG_41432.jpgEach port has to be configured for NT (acting as a phone line) or TE (acting as a client/phone device) mode.

Important bugfix: vhci_stat 1.3.1 released

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Important security update, I checked the wrong error condition in nvpair_lookup_*, so using -z on UFS volumes did not work (program segfaulted).


# vhci_stat -z
1.3.1; Pascal Gienger <>;
Host: seattle

PATH                                              WWPN,LUN            STATE
------------------------------------------------- ------------------- -----
   ZFS: pool name = atl1, ZFS Version: 4
   ZFS: size = 698.37G, member type = mirror
    /pci@1f,0/pci@1/fibre-channel@5/fp@0,0        210000d0231c50ab,1  ONLINE

Binaries for SPARC Solaris 10 and x86 Solaris 10 are included.

You may download vhci_stat-1.3.1.tar.gz here

MD5: 603e3a620085dc87197345687e4f740f  vhci_stat-1.3.1.tar.gz

More info is available on the vhci_stat-Page.

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