Introduction to algorithms

I highly recommend everyone to view this outstanding MIT course dedicated to algorithms and their efficiency. This course is especially interesting to those who, as myself, want to lift a veil of the education process in the US and how different subjects are being taught.

Abrupt clock change in SC

Today is 828 days after SC on one of ours SF6900 servers was rebooted for the last time, meaning that it’s exactly 828 days of uptime. And it’s one of the contributing factor to be beaten by 6567546 bug. Another one is the SC’s version and if its less than 5.20.7 – you’re affected as well. The impact is serious because this clock change can affect the domain time, database applications, customer data, or any other clock related operations. See the description of this bug for workaround or update SC to the latest Flash PROM version available.

Who cares about TCO and ROI?!

As expected people care less about buisness acronyms and high words i.e. TCO, ROI, integrted stack, when real money are involved. I visioned confirmation of this during Oracle+Sun welcome event where all Oracles’/Suns’ consultants were touting about their integrated stack but felt short once asked about the price the customer will have to pay for the new support contract or the license fee for using Oracle on Sun hardware. The innovations and green technology are cool but everything grows dim in the face of a bill. To sweeten the pill, it has been said that once the integration process is completed the price-list for Sun hardware will probably be revised towards reduction.

What was really useful about visiting this event is a talk in the corridors which gave a hope that:

  • Oracle will actually use its privilege of owning the whole stack (from software to disks) to make Sun+Oracle platform more winning and more attractive than any other competitive solutions from performance perspective.
  • Next SPARC64 processors and M-series platform, which are planned to hit the market in 2012, will be 50/50, against todays 20/80, in terms of Sun/Fujitsu partnership. It’s well-known that contemporary SPARC64 CPUs are more Fujitsu brainchild than Sun’s.
  • We were offered to take Sun T5220 equipped with SSDs and Sun Flash F20 PCIe for testing. Very sweet.

Tender thanks for invitation

As I mentioned in my last post there is going to be a planed Oracle+Sun welcome event on the 20th of May in Moscow Marriott Hotel and, nevertheless, I was a bit skeptical about my chances to be allowed to attend this event I still received the confirmation today. Frankly speaking, I don’t expect to hear any breathtaking revelations or confessions, they are all well-known from the similar events that have already taken place earlier in other countries, but anyway I expect it to be it a cheerful moment in addition to have a personal touch to the historical event.

See you there…

Who is swapping?

Yeah, I know that this has been already posted in other blogs many times before but to keep it more close for my own eyes I’ll re-post it here anyway. So, the following two series of dcmds could help you to figure out what processes have occupied the swap by listing their PIDs or executed commands respectively.

Note. This works in Solaris 10/Opensolaris keeping Solaris 8/9 out of the game.

echo "::walk thread thr |::print kthread_t t_schedflag|::grep .==0|::eval <thr=K|::print -d kthread_t t_procp->p_pidp->pid_id" | mdb -k

echo "::walk thread thr |::print kthread_t t_schedflag|::grep .==0 |::eval <thr=K|::print kthread_t t_procp->p_user.u_comm" | mdb -k

Disk replacement with VxVM

Be aware, that with Solaris 10 and VxVM MP3 a correct disk replacement procedure now looks as described here:

# vxdisk rm
Offline and Unconfigure the Lun
# luxadm -e offline /dev/rdsk/s2
# cfgadm -c unconfigure -o unusable_SCSI_LUN cX::
Cleanup/Recreate device Tree
# devfsadm -Cv
Recreate and Rescan VxVM devices.
# vxddladm stop eventsource
# mv disk.backup
# mv array.backup
# rm /dev/vx/dmp/*
# rm /dev/vx/rdmp/*
# vxdisk scandisks
# vxdctl enable
# vxddladm start eventsource

Otherwise, you’re going to put yourself at risk to admire the following error message every time “vxdct enable” command is invoked:

VxVM vxdctl ERROR V-5-1-0 Data Corruption Protection Activated – User Corrective Action Needed
VxVM vxdctl INFO V-5-1-0 To recover, first ensure that the OS device tree is up to date (requires OS specific commands).
VxVM vxdctl INFO V-5-1-0 Then, execute ‘vxdisk rm’ on the following devices before reinitiating device discovery:

Stumbled upon this issue myself, when replacing two disks in D240 JBOD.