Tag: solaris

No ZFS Support for EMC Replication Manager

As I originally blogged, I was hoping to use EMC snapshots to perform server-less/network-less backups. EMC provides two main tools for managing snapshots in this type of situation:

  • EMC Replication Manager
  • EMC PowerSnap Networker Module

The PowerSnap Module supposedly automates taking snapshots for the purpose of backups, while Replication Manager supposedly provides a much more robust package.

With Replication Manager you might create a policy to take a snapshot every five minutes, keep the last 10, and use those for backups whenever necessary.

To make a long story short, Replication Manager is useless for LUNs with ZFS. According to EMC, this won’t change in the near future. PowerSnap also has no support for taking snapshots of LUNs with ZFS on them so basically EMC has no server-less backup offerings for Solaris with ZFS.

As an IT guy in general, ZFS is the best thing that has happened to file systems in the last 10 years and it is only getting better. ZFS is already standard in FreeBSD and NetBSD. Linux supports ZFS over FUSE due to license issues but I’m confident those will be solved. The file system is platform independent, meaning you can move the data transparently between Intel and Sparc architectures. Deduplication has just been added to the feature set and disk encryption is on it’s way.

As a Solaris admin, I really can’t figure out why EMC would decide to cut off their own foot like this. It is clear that UFS will remain for legacy and backwards compatibility but ZFS is the future. Not planning to support ZFS is like not planning to support Solaris.

The only possibility that I can see is that EMC sees Sun, Solaris, and ZFS as enough of a threat, that they are strategically trying to limit options? For operations local to a server, ZFS has largely replaced the need for heavy hardware like EMC on the SAN. Some would argue that ZFS RAID + JBOD is better than ZFS + RAID on EMC. You can do the snapshots without the EMC. On a simple level, you can send snapshots asynchronously to another system, similar to MirrorView, without the EMC. You can do deduplication without the EMC. Now with Sun’s Flash Cache technology which integrates with ZFS, you can get the performance without the EMC. Along the same lines, you see Sun changing the rules of the storage/database game with solutions like Exadata V2. The integration of Zones with ZFS may be challenging Vmware on the virtualization front, especially with the serious advantage Sun’s Coolthreads servers have in terms of consolidation.

That said, I still prefer to offload this work to dedicated storage hardware for the time being and probably in the future. If EMC chooses not to support ZFS, they will only force us not to buy EMC arrays. We will stop buying disks, stop buying tools, etc.

Instead, they should be providing better support for ZFS, integrating with ZFS to get better performance, providing tools which make EMC the preferred disk array behind a ZFS filesystem.

Making Path Persistent

I’ve been paying a lot of attention to this site since I switched platforms and somehow people are finding some fairly irrelevant content on my site for the search terms making path persistent in solaris 10 so I figured I better put some real answers up.

It is hard to know exactly what kind of path they had in mind- were they referring to the standard PATH variable which lists the directories in which to search for executables or were they referring to something more complicated?

You can make the executable search PATH variable persistent in several ways:

  1. On the system level you can set it in the /etc/profile file. It will affect all users except maybe root.
  2. On a per user level, or for the user root, you can set the PATH in the .profile file in the user’s home directory

Issues Running Java Programs Remotely via X

Recently I started using SmartSVN running remotely on a Solaris 10 server and displaying on my Windows XP machine via Xming (the free Xserver). I quickly ran into some performance and usability issues which I hope to have solved.

  • Performance:
    1. Xming uses OpenGL for rendering by default. I added the following option to the java command line: -Dsun.java2d.opengl=true
      I’m not sure this technically made a difference but a developer claimed a 300% performance increase??
    2. Since I am working over a LAN, I disabled compression for the SSH connection being used to tunnel X and set my preferred cipher to Blowfish. Again- I’m not sure this made a difference but theoretically it should be faster.
  • Usability:
    1. There is an apparently known issue with running Java programs via X which causes all sorts of problems in painting the windows correctly. In my case, the mouse position was being shown in one place but the menus were being highlighted about 50 pixels lower. It took me a while to find it in this postabout Swing on Remote X and this related post about cursors and menus in NetBeans. Of course, after finding it in Google, I found the following comments in the SmartSvn start script:
      # If you experience problems, e.g. incorrectly painted windows,
      # try to uncomment one of the following two lines
      #export AWT_TOOLKIT=MToolkit
      #export AWT_TOOLKIT=XToolkit

      Uncommenting the export AWT_TOOLKIT=MToolkit did the trick. Now the menus are much more responsive and the cursors show in the correct position.

I’m not sure if the problem here is in XToolkit or in SmartSVN. I’m also not sure what this will mean in future versions of SmartSVN. Apparently JDK7 will not support MToolkit so either XToolkit has to work properly by then or SmartSVN has to be fixed to use XToolkit properly.

EMC Replication Manager in Solaris

UPDATE: No ZFS Support for Replication Manager in the near future

Using storage level snapshots can be used to run backups without directly requiring resources from the original host.

EMC Replication Manager coordinates the creation of application consistent snapshots across all the hosts in your network. It handles scheduling creation/expiration of snapshots,  mounting and unmounting from backup servers, etc. from a single console.

Although it is not tightly integrated into EMC Networker like the similar Networker PowerSnap module, it can be used to start a backup process after taking a new snapshot and it has the capability to manage snapshots unrelated to backups from a GUI.

While the data sheet claims support for Solaris, there are several caveats which I have run into.

  1. There is no mention of ZFS support in the data sheet and apparently, there is no support in the software either. One would expect this to be a non-question since ZFS has been part of Solaris since 2006.
  2. The data sheet is missing the word “SPARC” next to the word Solaris. There is no support for x86.

Honestly, this has put a dent in my plans since my backup server is an x86 box. I’m hoping the lack of ZFS support will work out as long as we can script any FS specific magic we need. I don’t have an option of running something like Linux on it (just to get the software working) because I won’t be able to even mount the ZFS filesystems- let alone back them up.

In the meantime, I’ll have to move my backups to a SPARC server and considering the lack of low end SPARC machines, I’ll have to allocate something way too expensive to be a backup server.

Webservd Default Home Directory

Someone currently building an internal development environment required some integration between servers using SSH and the webservd user.

He came to me when he saw that the default home directory for the webservd user is /.  He didn’t want to create a /.ssh/authorized_keys file and I didn’t blame him. My first reaction was to change the home directory but I didn’t want to break something so I opened up Google and found something incredible.

DISCLAIMER: The following is quoted from documentation at docs.sun.com (emphasis is mine). I do not recommend you actually listen to it’s instructions:

If the runtime user of the OpenSSO Enterprise web container instance is a non-root user, this user must be able to write to its own home directory.

For example, if you are installing Sun Java System Web Server, the default runtime user for the Web Server instance is webservd. On Solaris systems, the webservd user has the following entry in the /etc/passwd file:

webservd:x:80:80:WebServer Reserved UID:/:

The webservd user does not have permission to write to its default home directory (/). Therefore, you must change the permissions to allow the webservd user to write to its default home directory. Otherwise, the webservd user will encounter an error after you configure OpenSSO Enterprise using the Configurator.

Did someone actually write in documentation to give the webservd user write access to / ?!?!? What were they thinking?