• Mac OS X,  Xsan

    Resetting an Xserve RAID Controller

    To reset RAID Controllers on an Xserve RAID: Reset the NVRAM to return the XRAID to factory default settings by holding down the reset button on the back of the controller for 5 seconds and then releasing the button. If you need to reset both controllers, you should reset the lower controller first and then reset the upper controller. The Xserve RAID will now have the name Xserve-RAID and an automatic IP address. The location and contact information are also reset. The settings for drives, drive cache, prefetch and other array based information will not be reset. If you only want to reset the password of an Xserve RAID you…

  • Mac OS X,  Xsan

    Rebuilding Arrays on Xserve RAIDs

    Sometimes a drive fails, or a RAID controller goes down on an array with a redundant drive (eg – RAID 5 or RAID 3) and the parity on a RAID must be rebuilt. This should happen as quickly as possible. However, it can result in data loss and in the event of a second drive failure on the array most of the data could be lost. The data may be safe, and should be backed up as quickly as possible. Once the data is backed up, then you should perform a rebuild of the parity for the array. To do so open RAID Admin from /Applications/Server and click on the…

  • Mac OS X Server,  Xsan

    Xserve RAID: Reset Controller

    Unmount any Xserve RAID volumes hosted by the RAID (especially Xsan volumes).  Press the reset button  on the back of the controller module for about ten seconds.  You should see the controller restart and then the controller should be reset.  Sometimes you need to reset both controllers.  You don’t have to reset the whole controller to just reset the password.  To do that, you can press the reset button for about 1-2 seconds and then try to authenticate through RAID Admin to reset the password.  By default the password to view the Xserve RAID, once reset is public and to edit settings, the default password is private.  By default the IP…

  • Xsan

    Planning For Xsan

    Note: This article is now out of date. While the Apple Xserve RAID is still found in legacy installations, it has been replaced by the Promise RAID for new installations. The most typical storage found in Xsan setups is the Apple XRAID. Any XRAID will work within an Xsan deployment. XRAID systems being used in an Xsan should have the maximum amount of RAM available, which is 512MB. The Apple XRAID comes with 14 drive modules. Drive modules in an XRAID are split into two channels, each with 7 modules. Drive modules are just UltraATA or SATA enclosures for the Hard Drives used in an XRAID. XRAIDs are available in…

  • Xsan

    The Anatomy of a RAID

    Originally posted at http://www.318.com/TechJournal The acronym for RAID can often be misleading as it has had multiple meanings over the years. RAID originally stood for a redundant array of inexpensive disks. The acronym RAID is now also known as a redundant array of independent disks as not all RAID disks are inexpensive. RAID refers to a hard drive storage mechanism using multiple hard drives to share or replicate data among the drives. In some cases this can mean having data that is written to a single logical drive stored on multiple drives so there is redundancy of the data or RAID can be used to maximize throughput to drives by…