Thursday, May 31, 2007

PDO remove period in MPIO DDK

The PDO remove period is used when the last path to the LUN has gone missing and allows the virtual PDO (the one seen by disk) to stick around for a short while. A delay in removing it covers the case where the path comes back quickly (such as a transient condition) and avoids excessive processing time for PnP to scan luns, and rebuild stacks. You want to keep this as short as possible to avoid I/O hangs in the system.


An updated Storport storage driver

People may find problems when they using MPIO software on Windows platform with dual controller storage subsystem. I have encounter such problems like failback failed while failover is pass. The root cause is that storport driver of HBA need update with Microsoft's fix. Which fix can be downloaded at

This update addressed IOCTL_STORAGE_BREAK_RESERVATION issues.This update modifies the port drivers so that an IOCTL_STORAGE_BREAK_RESERVATION request that is sent to the port LUN (which is the physical device object (PDO)) is forwarded to the adapter (which is the filter device object (FDO))

I used this update adressed ALUA issue and link failed issues like link plug off.

Tuesday, May 1, 2007

Using Xen as Build Server.

Over the past few years Our build server machines have increased  to meet differece Windows and Linux platforms. For example on Linux 2.4 kernel and Linux 2.6 kernel Platform, each platform should installation on two and more machines for deploying specialized toolchain compilers.

However, this adoption of build servers, particularly for stabilization solutions, has led to machine bloat -- towers and racks of multicolored boxes, each performing a specialized build.

About half years ago, I installed a Xen 3.0.3 server with 2 GB memory, moved the Linux build server's function to the Xen server. After two weeks of stabilization test, all  runs smoothly .