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Tiny Deathstars of Foulness

Setting up iSCSI to work with ESX is usually a pretty straight forward affair. But like with many things, change can be hard. But sometimes things get moved to different subnets or storage gets replaced. To configure a vSphere client to connect, select a virtual machine and then click on it and click on the Configuration tab. From there, click on Storage Adapters using the Hardware panel. From the Hardware Panel, click on an initiator and then click on Properties and then click on Configure. Then provide the new name or IP. Make sure that the name is unique and then if needed provide an iSCSI alias. Then change the IP settings if needed and click on save. New iSCSI sessions can be used immediately whereas old sessions will require you to logout and then log back in.

June 13th, 2012

Posted In: Network Infrastructure, VMware

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The latest version of VirtualBox is out and it supports a whole slew of bug fixes. In fact, the latest VirtualBox fixes a very specific problem that I’ve been struggling with, which is the fact that iSCSI LUNs greater than 2 Terabytes would not mount (not that I have many LUNs greater than 2TB in my lab but occasionally it does come up). When running on Mac OS X, the following other bug fixes are also included:
  • X11 based hosts: allow the user to specify their own scan code layout (bug #2302)
  • Mac OS X hosts: don’t auto show the menu and dock in fullscreen (bug #4866)
  • Mac OS X hosts (64 bit): don’t interpret mouse wheel events as left click (bug #5049)
  • Mac OS X hosts: fixed a VM abort during shutdown under certain conditions
Overall, VirtualBox + OpenStorage continues to become a strong offering from Sun and in my labs at least it’s becoming more and more my weapon of choice for rapid provisioning of test VMs and the management of my lab storage. I’m not saying I would put hacked up versions of Mac OS X Server as a guest OS (on Apple hardware of course;) in VirtualBox into an actual production environment, BTW (nor condoning doing so in all seriousness)… Anyway, VirtualBox 3.1 is workin’ like a charm…

December 1st, 2009

Posted In: Mac OS X, Mac OS X Server, Mac Security, Ubuntu, Uncategorized, Unix, VMware

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Drobo + 4 1.5TB Disks = 6TB of storage for ~$730 Perfect for iSCSI targets and TimeMachine backups, not-so-much for editing uncompressed 1080p…

September 10th, 2009

Posted In: Mac OS X, Mac OS X Server

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How to use iostat to triangulate disk speed (IO) issues on Mac OS X & Mac OS X Server

How to use iostat to triangulate disk speed (IO) issues on Mac OS X & Mac OS X Server

August 6th, 2009

Posted In: Mac OS X, Mac OS X Server

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Now that I’ve shown over the years how to setup an Xsan and iSCSI targets on Mac OS X I am starting to get a number of questions about how to set these up in such a way that Time Machine can backup to them.  Since they’re not your typical disks in a lot of cases there’s a small command that you’ll need to run to make it work: defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1 Essentially, once you’ve run this command you’ll be able to back up to anything that appears in /Volumes and then some (for example share points on your local network might appear even if you haven’t yet authenticated to them).  You’ll also be able to backup to disks that are direct attached to an AirPort Extreme (which essentially makes them NAS volumes over an up-to-802.11n medium).

December 21st, 2008

Posted In: Mac OS X, Xsan

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Using iSCSI targets with Xsan… Don’t do this one at home kids.  It’s just silly and not going to be supported by anyone…  But if you are like me then you can do it if you must.  So to get started with iSCSI check out this article. When you have a LUN that is connected don’t yet assign it a file system (or if you have partition it back to free space). Now install Xsan but don’t yet create a volume. Once you’re done, you can go ahead and fire up your trusty Terminal app from /Applications/Utilities. Type in cvlabel -l which should show you all your available LUNs. Next, type the following, which will dump your cvlabel information out to a file called labels: cvlabel -c >labels Now that you have your file open it in your favorite text editor and change the very first text field to read what you want your LUN to be called within Xsan Admin. Once you’re satisfied save the file. Now, use the following command, which will read the file you just edited and then label the LUN for use with acfs using the name you just provided, making it appear in Xsan admin: cvlabel labels Now you can open up Xsan Admin. Here, click on LUNs in your SAN Assets. Make sure that the LUN you just labelled shows up as seen below.
iSCSI LUN in Xsan Admin

iSCSI LUN in Xsan Admin

Next, click on Volumes in your SAN Assets and then click on the plus sign (+) to create a new Volume.  At the Volume Name and Type Screen, enter the name you would like your volume to be called, customize the Volume Type and advanced fields for any performance tuning you would like to do and then click on the Continue button to proceed.  
Xsan Volume Name and Type Screen

Xsan Volume Name and Type Screen

At the Configure Volume Affinities tab, drag your LUNs into the appropriate Storage Pools.  For this example we only have one storage pool so we won’t be needing the additional items listed here.
Xsan Configure Volume Affinities Screen

Xsan Configure Volume Affinities Screen

Next click Continue, assign the metadata controllers to your volume and then click Continue again.  Your volume will now mount on the desktop and be listed as can be seen below.
Xsan Volumes with iSCSI Storage

Xsan Volumes with iSCSI Storage

Once again, this article shows you how to do something that you should likely not put into production.  Having said this, iSCSI can be great for some uses, but when used in conjunction with Xsan and the apple clustered file system (acfs) you might be best off sticking with fiber channel…

December 14th, 2008

Posted In: Mac OS X, Mac OS X Server, Xsan

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iSCSI is a network storage protocol that allows sending and receiving of SCSI commands over a TCP/IP network. This allows you to leverage Ethernet, a low cost network medium to get SAN performance and network based storage. While you can use pretty much any Ethernet switch, I’d recommend that if you’re going to use iSCSI that you dedicate a switch to it, or use quality switches and build a dedicated VLAN for your iSCSI traffic. Recently, I’ve recently been seeing a lot of traffic about whether or not you can use iSCSI with Mac OS X. The answer, yes. As with Xsan, to get started with iSCSI you’ll need an initiator and a target. Studio Network Solutions (SNS) provides a software-based iSCSI initiator called globalSAN that can be downloaded and used free of charge from their site. Alternatively you can also look into the Atto Xtend SAN, which runs about $200 for 1 user with volumes discount slashing the prices to about $90 for 100 users. Software based initiators will use the CPU of your system and a built-in or third party standard Ethernet port, but you can also buy a dedicated card which will offload the processing power to the card, which in some cases will be required for various performance reasons. For the purpose of this article we’re going to use the SNS globalSAN software. For the purposes of this howto, we’re using the free version of software called Starwind from RocketDivision. However, we’ve also tested LeftHand, Isilon, OpenFiler, iSCSI Target (from Microsoft) and many others (including dozens of appliances) with the Mac. So for starters, fire up your iSCSI storage and share it out. Next, extract the installer as seen in the globalSAN installer screenshot.
globalSAN Installer

globalSAN Installer

Next, launch the installer and click on the Continue button at the Welcome screen.
globalSAN Welcome Screen

globalSAN Welcome Screen

At the Software License Agreement screen, read the licensing agreement and then click on the Continue button if you agree to the terms.
globalSAN License Agreement Screen

globalSAN License Agreement Screen

At the uninstall screen, click on continue. If you later need to uninstall the software you would re-run this installer and click on the Uninstall button.
globalSAN Uninstall Screen

globalSAN Uninstall Screen

At the Standard Install screen you can click on the Custom Install button to allow you to choose which packages within the metapackage to install. It is best to leave them all checked and then click on the Continue button.
globalSAN Custom Install Screen

globalSAN Custom Install Screen

Provided everything installs properly you will next be at the Installation Completed Successfully screen. Here, click on Restart and then log back into the system when it comes back online.
globalSAN Installation Successful Screen

globalSAN Installation Successful Screen

Once you are logged back in, open System Preferences and you’ll see the new System Preference for globalSAN iSCSI.
System Preferences with globalSAN Pane

System Preferences with globalSAN

If you click on the globalSAN System Preference you’ll be able to add your first portal. Each share will have a unique IP and be referenced as a portal. Click on the add icon (+) to add your first portal.
globalSAN Portal Screen

globalSAN Portal Screen

At the dialog box, type in the IP address of your iSCSI target and the port number, which defaults to 3260 for a majority of the products you may use.
globalSAN Portal Dialog Box

globalSAN Portal Dialog Box

If you require authentication to your target then click on the Advanced… button and enter the pertinent information (Kerberos is not yet supported as an authentication method but CHAP is).
globalSAN Advanced Dialog Box

globalSAN Advanced Dialog Box

You can also click on the IPSec tab if you use IPSec for authentication on your targets.
globalSAN IPSec Setup Tab

globalSAN IPSec Setup Tab

Click OK to add your portal and you will be taken back to the Portals tab of the globalSAN System Preference. Here you should see your portal listed. If you don’t, click on the Refresh button.
Populated globalSAN Portals Tab

Populated globalSAN Portals Tab

Now that you have your portal populated, click on the Targets tab and you should see the storage listed. Click on it and then click on the Log On button to initiate your session into the storage. At this point, it will mount on the Desktop (provided you have already given it a file system) and you will be able to use it as you would any other storage. You can check the box for Peristent if you would like to have the volume always mounted on the system.
globalSAN Targets Tab

globalSAN Targets Tab

If you click on the Sessions tab then you will be able to look at various statistics about your storage including the LUN identifier and disk name.
globalSAN Sessions Tab

globalSAN Sessions Tab

If you don’t yet have a file system on the storage then you can go ahead and open Disk Utility and you will see the storage listed there, click on it, click on the Partition tab and you will then be able to give it a file system.
Disk Utility with iSCSI Storage

Disk Utility with iSCSI Storage

So it’s pretty easy to use iSCSI with Mac OS X. We didn’t have to open Terminal or do anything crazy in the least. It just works and while it’s not going to be as fast as something like fiber channel, it also doesn’t come with the costly infrastructure requirements that fiber channel comes with. The LUNs can be accessed by multiple hosts provided that the file system supports that. However, HFS+ does not support iSCSI, nor do any of the current file systems for the Mac that we’ve tested other than acfs (Apple Clustered File System)/cvfs, the file system for Xsan.

December 13th, 2008

Posted In: Mac OS X, Mac OS X Server, Xsan

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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 to your policies on RAID levels, etc. To expand a volume first add the storage and do not allocate it to a volume or create a disk out of it.  Leave it as free space.  Then, while logged in as an administrator, open Administrative Tools from the Server Manager.  From here, click on Storage and select Disk Management.  Then right-click on the disk you wish to expand and click on Extend Volume, which will open the Extend Volume Wizard. Click on the free space to add to the disk from the list under the Available column, which will move it under the Selected column.  From here you will be given a value (in MB) for how much to extend the volume.  This cannot be greater than the number listed in the Maximum available space in MB field.   Once you are satisfied with the storage you will be adding into your logical disk click on the Next button.   Read the overview of what will be added, taking note to verify that the total number of MB is not greater than what is available and click on the Finish button.  Now wait and viola your disk should now be bigger. You can also do this through the command line by using the diskpart command.  Basically, you select a partition from a disk by doing select disk and then select partition (you can list disk and list partition to see what you will be managing).  Then use the Extend Size= variable to define how much to extend it by (by default it will just use all the space so you don’t have to set this if you don’t want to).  Once done type Extend and you’re off to the races.   Once again, I need to emphasize that whole redundancy thing.  If you add a single disk into a volume that was RAID 6 then you’re going to be in a far less redundant scenario.  When possible preserve the RAID type for the original media. An alternative to this process is to use a couple of different strategies.   The first is to use a symbolic link provided the application can traverse one.  You can symlink a folder from one drive onto another.  You can do this using the mklink command.  Using symbolic links may allow you to temporarily isolate what data will go onto, for example, a near line disk being used temporarily as online storage.  This can be useful in situations where you plan on adding a larger disk that is fully redundant later and just need to put your data somewhere in the meantime. Another option is the subst command.  Using the subst command you can basically map a drive letter to a folder on the computer.  This will effectively mount up a path as though it were a network share, used similarly to the NET USE command.  A final option from back in the day is to use the append command, but I think this one was not included with Windows Server 2008 so don’t quote me on that… So another point to make is that the process for expanding a volume works with internal media and external media.  So if you have, for example, a fiber channel disk array or some eSATA storage you can expand an internal disk (let’s say C: or D:) to include this media.  So given a full array of internal disks and no available expansion slots you can fairly easily go ahead and add more media even if you are out of internal space.  Ergo, from a storage standpoint, you can almost always upgrade provided you have an extra PCI or PCI-X slot on a Windows Server.  Or you could theoretically use iSCSI storage, although I haven’t personally gone this route in this type of situation…

October 11th, 2008

Posted In: Windows Server, Windows XP

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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

June 12th, 2008

Posted In: Windows Server

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