the answer is no. At least when it comes to the number of bytes they promise you can store on their drives they’re not. Oh really?
In July 2012 I wrote a blog post on “saying what you mean to say“, so people cannot misinterpret what you’re trying to point out. Gigabyte, Gibibyte, Joules, Calorie, kilo Calorie, degrees Celsius, but not degrees kelvin (it’s just kelvin or capital K).
From Monday April the 15th to May 1st 2013 EMC is hosting yet another “Ask the Expert” discussion on ECN. This time it’s about Fibre Channel Routing.
What is it, what’s it used for and how do you know if you want it?
Take a look at the discussion and join me and my friends Allen Ward and Mr Dynamox on ECN!
And although we close the topic on May 1st, we’ll wrap up LIVE from EMC World in Las Vegas in the EMC Elect corner! So if you’re there from May 6 to May 9, make sure to look out for us. As far as I know the Elect corner will be next to the Blogger’s area, close to the Pavillion.
So what else is there that differentiates SCSI, (P)ATA, SAS, NL-SAS and SATA?
In part 1 we talked about Rotations Per Minute and Command Queuing, but what else is there that makes a certain drive a better choice than any other? Other differences are the size of the platters. Commonly used are 3.5 inch and 2.5 inch. Although it makes sense that smaller platters can rotate faster than larger platters in the end only the size of the drive cage matters. It’s in fact somewhat weird that most 2.5 inch drives now rotate at 10k RPM and the 3.5 inch drives at 15k. Being able to cool the device is probably the main reason why a 10k drive only spins at 10k RPM. If it would rotate any faster, it would heat up more and heat dissipation could become a serious problem. So if you need a high GB per square meter density and performance doesn’t really matter, then the 2.5 inch drives make sense, but if performance is the key differentiator, the more IOps you can squeeze out of each drive, the better. And since we’re not discussing data center designs here, only quality / performance counts.
Everybody needs storage space nowadays. Whether it is used for high performance computing or simply storing family snapshots, we all need room to store data which is important to us.
In the old days (the 1990s) things were fairly easy: you had either ATA or SCSI. The much older RLL and MFM are now called ancient and therefore not talked about in this article. ATA was mainstream for about 10 years and SCSI was expensive, but also very fast. Both standards used a flatcable and the data was sent to and from the drive in parallel. But when speeds increased the timing of each of the separate signals became difficult and just like cd players in the 1980s manufacturers started using serial lines. This meant that higher speeds could be accomplished and also that the huge flatcables were now traded in for much smaller cable, which improved the airflow as well.
If you somehow need to get some work don on your power feeds to your data center and the VNXe needs to be shut down, you need to manually shut down the machine before starting the work on the power lines. But knowing CX and VNX, this proved to be a challenge for me since the e model doesn’t have Standby Power Supplies. These SPSs used in CXs and VNXs do the work for you: when you turn the power switch on the SPSs or simply cut the power feed to these SPSs, the SPSs send out a signal to the Storage Processors, which will then flush the write cache to the vault after which the SPs will shut down nice and orderly.
But how do you do this on a VNXe model?
The best way is to do this from your desk! you don’t even have to get up and walk to the VNXe at all! There are two ways you can shutdown the VNXe.
uemcli -d <IP_address> -u service -p <Service_password> /service/system shutdown
The Unisphere CLI (UEMCLI) should be downloaded from the EMC Support website and should be installed on your pc (Windows/Linux/Solaris/Unix). After installing this CLI you can execute the mentioned command to shutdown the VNXe. There is a Unisphere CLI user guide available on the EMC Support website.
In the older versions of the VNXe operating system there was no CLI option to shutdown the unit. The svc_shutdown command from the console (Putty) was the only way on those older machines. However this will not completely power down the system, it will unload all software from memory. After issueing this command a power loss won’t damage the data (like LUN corruption, OS image corruption, cache dirty etc.).
EMC Elect 2013, 2014, 2015, 2016 and
Dell EMC Elect 2017
Follow me on social media