With Apple bundling Xsan into Lion and opening up more storage options than before, it seems like time to start exploring alternatives to Promise Vtrak’s for Xsan storage. ActiveStorage makes a very nice RAID chassis and should be shipping metadata controller appliances soon. I’ve discussed both here before and they make for very nice kit. But in order to have an ‘ecosystem’ you really need a little biodiversity. And the Xsan environment needs to become more of an ecosystem and less of a vendor lock-in situation. So another option that I’d like to discuss is the Rork Aurora Galaxy. These little firecrackers have a lot of potential upside: 4 8Gbps…
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Fibre Channel Switches vs. Hubs
In the FC-AL (Fibre Channel Arbitrated Loop) protocol, when devices enter loops, they send out a Loop Initialization Primitive (LIP) request for an address. All other activity on the loop then comes to a halt as each node reestablishes its connection. Since a hub-based fabric is one large arbitrated loop (which can in many cases similarly be built without the actual hub but with less aggregated speed), it must be entirely rebuilt every time any device is rebooted, added to the loop or removed from it. This causes the potential for processing errors, iNode issues/volume errors and even physical disk failures. A “LIP storm” can also cause multiple devices to…
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Windows Server 2008: Expanding a Volume
You may find that a disk in Windows Server simply isn’t big enough for your greedy applications. But never fear, the good folks at Microsoft have given us the ability to expand that volume on the fly, as needed by adding other pools of storage or single disks to it. However, it’s important to keep in mind that if you have a highly available volume (let’s just say a RAID6) and you add a single disk to it then you have just effectively lost the high availability for the data stored on the extended portion of the volume. So make sure that the new storage you are adding matches up…
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iSCSI Target Creation
The iSCSI Initiator that we use for connecting Windows to iSCSI targets has a friend. It’s called Microsoft Windows Storage Server, which you can use to turn a DAS RAID in a Windows box into a LUN for iSCSI. Good stuff. Check out the data sheet here: download.microsoft.com/download/d/8/4/ d84b1c50-e0bb-45ba-b2f4-356f4f456a88/WUDSS%20Datasheet_Final.doc Now that’s not to say they’re the only game in town. iSCSI Target is also a feature of OpenSolaris: http://opensolaris.org/os/project/iscsitgt/ And there’s a nifty little Open Source Project called iSCSI Enterprise Target: http://sourceforge.net/projects/iscsitarget/?abmode=1
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Xsan: Reset Qlogic Password
Lost the password for your Qlogic? You can TFTP a new firmware file into a 5xxx switch and then do a factory reset while it’s in maintenance mode (follow the instruction exactly as they are in the latest version of the manual for your switch). Or if you have a serial adapter you can break the boot sequence by using the space bar during boot. At the prompt use: factory 1 If you factory reset it then the default IP address will be 10.0.0.1 again and the default password will be back to password. If you have the password and just want to reset it back to factory defaults then you…
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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…