Many years ago, before there were Xserves, in an attempt to save rack space in our cabinets, we experimented with ripping the guts out of a PowerMac G4 and stuffing them into a 2U server case. Here is a photo of one of those attempts:

It worked out fairly well and we had a couple of these running for several years.

The main piece to the puzzle was finding the right L riser card to give us access to the AGP slot and 2 of the PCI slots, one for a secondary Ethernet card and another for an ATTO SCSI card.

Posted by Brian Blood as Colocation, Hardware, Servers at 10:15 AM CDT

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Server Monitor is an application that allows you to monitor the health of several Xserves over the network:

Sometimes the application gets a bit cranky about the connections it makes to the servers and reports that it can’t communicate or as you see here in the picture “reply not understood”. So we don’t really use it for serious monitoring other than as a cursory glance usually to check some items.

However, Apple really takes the cake with this knowledge-base article:

Xserve: Server Monitor does not authenticate with server over subnet

in which they claim that the way to fix the problems with their SOFTWARE, is to:

1. Make the necessary changes to the username or password using Server Monitor.
2. Quit Server Monitor.
3. Shut down the Xserve that is the target of these changes.
4. Remove the power cord from the back of the Xserve.
5. Wait 30 seconds and plug the power cord back in.
6. Power the server back on.

This sounds suspiciously similar to something an old tech friend of mine once told me:

There are sound scientifically proven reasons why one must sometimes sacrifice a chicken in order to get a SCSI chain to work.

Ugh.

Posted by Brian Blood as Colocation, Hardware, OS X Server, Servers, Soap Box at 11:33 PM CST

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It has come to my attention that the thumbscrews on the front panel of Xserves are a very important component of the overall structural integrity of the rack mounting system. they not only keep the Xserve from coming out of the case, but they also secure the forward portion of the server to the mounted top case. I’ve seen many Xserves that seemed as if they could pop out of their cases due to a small amount of bowing in the case. Having the thumbscrews tightened down adds another vertical support component.

Posted by Brian Blood as Colocation, Hardware, Servers at 11:54 AM CST

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A client of ours is moving his servers to a new colo soon and like us, uses QuickDNS from Men and Mice to manage his BIND installations. He needed an AppleScript that would go through all his zones and reduce all the TTL values so that when he moved his servers, the transition would happen as smoothly as possible. So I whipped up this AppleScript:

set setDirection to "low"
--set setDirection to "normal"

tell application "QuickDNS Manager"
  repeat with theZone in zones
    set curZoneName to name of theZone
    set theDoc to (open theZone)
    tell theDoc
      if ("low" is setDirection) then
        set default time to live to 7200
        try
          set expire of first SOA record to "1400"
        end try
        try
          set refresh of first SOA record to "7200"
        end try
        try
          set negative caching of first SOA record to "7200"
        end try
        try
          set retry of first SOA record to "3600"
        end try
        try
          set time to live of first SOA record to "7200"
        end try
      end if
      if ("normal" is setDirection) then
        set default time to live to 7200
        try
          set expire of first SOA record to "604800"
        end try
        try
          set refresh of first SOA record to "28800"
        end try
        try
          set negative caching of first SOA record to "43200"
        end try
        try
          set retry of first SOA record to "7200"
        end try
        try
          set time to live of first SOA record to "86400"
        end try
      end if

      save with comment ""
    end tell

  end repeat
end tell

Posted by Brian Blood as Colocation, Servers at 5:39 PM CDT

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Datacenter Power. It seems you can never have enough.

We have our colocation inside an Equinix IBX. It is an excellent facility. Unfortunately, about 2 years ago, our cage got a new neighbor. They have added rack after rack of new servers to accommodate their ever increasing traffic. Which means they have effectively used up all the allocated power feeds for our section of the colo.
So as we started to fill our own cabinets, we found that we were quickly using up the 2 x 20A 110V feeds they had allocated to each of our cabinets. Our partner in colocation, sell.com was also at this time upgrading their farm to the latest dual xeon models. These boxes were pulling a LOT more amps than the previous P3 generation.

Very quickly, we became experts on how much amperage we could squeeze out of our existing feeds and what systems required how much power.

Here are some anecdotal amperage readings we took from our fancy amp reading tool.

Dell PowerEdge 2850

Specs: Dual Xeon 3.6GHz/1MB; 6 x 73 GB SCSI Hard Drive (10K RPM); Dual Power supplies

• PS A & B both active
  • PS A - 1.15A
  • PS A & B - 2.35A
• PS A only - 2.30A

Dell PowerEdge 1650

Specs: Dual PIII 1.4Ghz; 2GB RAM; 3 x 36GB SCSI 10K rpm; Dual 275W Power supplies

• PS A & B both active
  • PS A - 0.7A
  • PS A & B
    • Nominal operation - 1.41A
    • Warm Boot - 1.44A Peak
    • Cold Boot (drives spinning up) - 1.56A
• PS A only
  • Nominal operation - 1.37A

Apple Power Mac G4

Specs: G4/533 Dual - 1.5GB RAM - 2 x 18GB SCSI (15K rpm)

• Peak Startup - 1.27A
• Max load on SCSI drives - big copy operation - 1.18A

Apple Xserve G4

Specs: Dual 1.0 Ghz G4, 2GB RAM 2×60GB & 2 x 180GB

• heavy cpu/disk load - 1.52A
  • simultaneous diskutil zero on all disks (booted from CD)
  • Max CPU - multiple threads of cat /dev/urandom > /dev/null & ssh/rsa keygen operations
• all 4 disks idle - 1.37A
• Insert 180GB ADM - peak 1.41A, settled back down to 1.32A
• Insert second 180GB ADM - peak 1.48A, settled down to 1.38A
• keygen and cat large data file generated by /dev/urandom, copied to Software RAID mirror 60GB - spikes to 1.56A

Apple Xserve G5

Specs: Dual 2.0Ghz G5, 3GB RAM, 3 x 80GB SATA

• Nominal operation - 1.8A
• Max Cold Boot - 2.16A

Apple Mac Mini

Specs: Intel 1.66Ghz Core Duo, 2GB RAM, 60GB E-Rated Hitachi drive E7K100 model

• Nominal operation - 0.29A
• Max cpu, disk activity - 0.37A

IBM 4000R

Specs: Dual 833Mhz PIII - Single Power supply - 2 x 18GB SCSI (10K rpm)

• Cold Boot (drives spinning up) - 1.0A
• heavy cpu/disk load - multiple instances of cpuburn and cat’ing /dev/urandom to a file - 0.9A
• Nominal operation - 0.75A max

IBM eServer x330

Specs: Two Intel Pentium III (Coppermine) 864MHz processors, 1GB RAM, Single Power Supply, Single 36GB SCSI drive

• Connecting Power Peak: 0.29A
• Stdby Steady: 0.11A
• Power On Peak: 0.78A
• SCSI spinup: 0.98A
• Powered low load: 0.63A
• Loaded (6.0+ Load Average with disk): 0.80A
• Disk activity only: 0.72 peakA
• Reasonable Load + Disk Activity: 0.79A
• heavy cpu/disk load - multiple instances of cpuburn and cat’ing /dev/urandom to a file - 0.82A

IBM eServer x336

Specs: Dual 3.0Ghz Xeon, 4GB RAM, Dual 575W PowerSupplies, Dual 146GB SCSI drives

• Connecting Power Peak: 1.06A
• Stdby Steady: 0.79A
• Power On Peak: 2.5A
• Powered low load: 2.12A
• Loaded (7.0+ with disk): 3.25A
• Disk activity only: 2.40A
• Reasonable Load + Disk Activity: 2.85A peak
• heavy cpu/disk load - multiple instances of cpuburn and cat’ing /dev/urandom to a file - 3.2A

Cisco 11151 Load Balancing switch - 0.89A

Cisco 3548XL Switch - 0.32A

Dave from NetApp has some interesting things to say about power in the datacenter.

Posted by Brian Blood as Colocation, Routers and Firewalls, Servers at 6:51 PM CST

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