I've been asked this question quite a lot lately, and to be honest I've been a bit stumped, other than a  gut feeling that monitoring from the OS as well as the VMware layer is a good idea, I had little else to offer the argument. So I figured I should take a more serious look at the monitoring available within VMware vCenter and come up with a more compelling argument. Perhaps the more seasoned VMware admins out their could comment to offer their thoughts on the topic?

vCenter for VMware provides an excellent selection of performance graphs enabling you to track the CPU, memory, network and I/O consumption for each VM as well as the ESX host itself. You can also set "alarms" that trigger e-mail notifications. So why would I ever need an additional agent based OS monitoring package? What more could you possibly need? Do the OS metrics become less important in a VM world?

Recently I have seen some strange behaviour with the later levels of firmware (around version 7.10 upwards) whereby a failed drive that has reconstructed to the hot spare does not automatically copyback when a new drive is inserted. The disk appears in storage manager as Optimal and Unassigned and logs indicate it has been picked up without error.

In later versions of IBM Storage Manager (versions 10.10 and up). There is a new function included "Replace Drives" that allows the user to select whether to replace a failed drive with any unassigned drive in the subsystem or the hot spare drive. It should be possible use this function to initiate the copyback. In some cases, I have seen that when the option "Replace Drives" is selected, the message is displayed "no drives available for replacement", despite the fact that unassigned drives are clearly available. In my investigations I have checked that the new drive was inserted correctly (leaving 30 seconds between the pull of the old and insertion of the new). I have seen that the new disk is of exactly the same type and brand and running the same level of firmware and that there do not appear to be any obvious problems within the event log,

The resolution so far has been simply to wait (even up to 2 days), and eventually, the "Replace Drives" option will recognise the available drive(s). So far, the only indication of what has occurred between these times has been that the regular media scan (scrub) has kicked off. Note that if a Storage Subsystem password is set, this is required to authorise the copyback.


The "Replace Drives" function does not appear to be clearly documented in the new Storage Manager client Redbooks so I will blog regards what I know of this function later.

Speak to one of our technical experts now to see how Centiq can help your business by requesting a "call back" using the button to the right, or calling us on 0115 951 9666

Be aware that unlike like IBM System Storage DS4000 series range, the cache batteries within the IBM System Storage DS3000 series Subsystems (including DS3200, DS3300 and DS3400) are not covered under IBM warranty. This means that when they fail a replacement part must be purchased even if the unit is under standard or uplifted warranty.

IBM state in Retain Tip H194543 that "the battery is designed to have a life expectancy of two (2) years and to maintain the data in cache for up to three (3) days in the event of a power outage".

The replacement part can be requested from your IBM Sales Representative or an IBM Business Partner such as Centiq. The part required is:
DS3000 System Memory Cache Battery, Option 39R6519

Retain Tip H194543 also recommends that users upgrade the subsystem controller firmware to 07.35.41.00 or later to benefit from the Smart Battery Learn Cycle technology which monitors battery life and will override the "Battery Nearing Expiration" warning if it determines that the battery is still in good order.

Note that in order to calculate battery life, the "Smart Battery Learn Cycle" performs a discharge and charge every 13 weeks during which time write cache will be suspended and this could impact on the performance of the system. This Smart battery feature can be disabled if preferred.

*A small set of batteries may not support this Smart battery technology - see the Retain Tip for more information*

For more information contact Emily on 0115 951 9666 or visit the Centiq website, Nottinghams Premier IT Specialists company.

As much as I'd like to say that IBM is faultless and standing proud above the competition, I can't say that in good conscience. Sometimes I feel nothing but frustration towards IBM and their desire to make things so unnecessarily complex and difficult. This is especially true when it comes to customer support, though in fairness to IBM this seems to be a common trend with most hardware or software vendors these days.

As a result I sometimes see support as a "wall". Not because a wall is a fundamental element to any building providing both reinforcement and safety for the overall structure, but simply because that's what it feels like my head is banging against when I'm talking with them.

 Capacity on Demand (CoD) is a feature of IBM's Power Systems designed to provide an easier way to upgrade your server resources when the need arises.

Centiq approved as Buying Solutions sub-contractor

Centiq, an IT consulting and services provider has been approved as a sub-contractor by Buying Solutions, the national procurement partner for the UK's public services. The accreditation will enable public service organisations, for the first time, direct and quick access to specialist IT skills previously only accessible by the time intensive tendering process.

Partnering with Buying Solutions' approved supplier European Electronique, Centiq has been selected because of its 11 years of experience in the public sector market. As an accredited business partner to technology providers, including IBM and HP, Centiq can offer local government bodies, NHS Trusts and other public service organisations a quicker route to solving IT problems or procurement of new IT systems specific to the public sector.

I'm currently writing a script which needs to parse a configuration file and for one reason or another I got in to the situation where I wanted awk to use one of my shell variables.  I had never needed to do this before so I searched for a little while before coming across a guide on Tek-Tips that explains three ways of doing this.

http://www.tek-tips.com/faqs.cfm?fid=1281

The IBM System Storage DS4000 cache battery provides valuable backup for the controller cache in the event of a subsystem power failure. The battery will allow the controller cache to be de-staged (i.e. written to disk) safely and ensure data remains consistent.
In older levels of controller firmware, these batteries were set to notify regarding an impending expiration at 36 months followed by cache disable action by the microcode at 39 months. When the cache disables, you could experience performance degradation since the controller's high speed cache is no longer in use.

IBM now state that in fact these DS4000 batteries can last well past 62 months and in controller firmware 6.60.02.00 and onwards a notification is now set to occur at 62 months followed by the cache disable action by the microcode a little after ten years.

I have found that when logging calls with IBM for the "Battery Nearing Expiration" notification, if the firmware is below 6.60.02.00 they simply tell me to reset the battery age to zero. Of course if the battery has actually failed then this would be replaced as usual under maintenance.

It's worth noting that there are no diagnostics to trigger the expiration notification and the date is purely hardset in microcode.

All this information was obtained from IBM retain tip H193840.
For more information contact Emily on 0115 951 9666 or visit the Centiq website, Nottinghams Premier IT Specialists company.

In our second part of "Solid State of the Art?" we're looking at how to use Solid State Drives, what applications we can best use them for, and what the future holds for SSD technology.

Believe it or not (or simply check Wikipedia), Solid State Drives (SSDs) have been around in their current form for nearly thirty years, however it's only within the past two years that they've really managed to gain any ground in more mainstream corporate usage. In this article I'll be discussing the various aspects of these drives, and when and where to use them.