Archive for the ‘Technology’ Category

EMC Symmetrix DMX3 and DMX4 Comparison

December 6th, 2008 1 comment

See how the DMX3 and DMX4 are compared side by side.  

Comparison is based on different DMX3 and DMX4 models for maximum number of drives it can support, total drive capacity, channels, global memory directors, max global and usable memory and different connectivity from host to the storage. 

With total number of drives fluctuating from 32 to 2400’s and capable of supporting more than 1 PB (PetaByte) of Storage onto a Single machine. 

With I/O Speeds going up to 4 GB on the Fiber Backend, its lighting fast. 

EMC Symmetrix – DMX Models by Cabinets Types

December 6th, 2008 1 comment

The below is the true breakdown of the type of the EMC Symmetrix and EMC DMX machines to the type of cabinet properties it has. 

Starting with the Symm 3.0’s EMC introduced a 1/2 Hieght cabinets, Single Full Cabinet and a 3 Cabinet machine. The same ideas went into the Symm 4.0 and 4.8. 

Starting the Symm 5.0 and into Symm 5.5, EMC introduced the Badger cabinets, which where much slimmer and about 5 ft in height, it was a disaster with those cabinets. Really no one bought it. 

Starting the DMX800’s and DMX1000’s which are the single cabinet, EMC introduced the DMX2000’s in 2 cabinets and DMX3000 in 3 cabinet style. 

Also if you ever wondered where those Symm modell numbers came from

1st Digit: 3 = Open Systems. 5 = Mainframe. 8 = Mixed.
2nd Digit: Related to Cabinet size, dependant on Generation’
3rd Digit: 00 = 5¼” Drives. 30 = 3½” Drives              

The DMX uses 31/2″ Fiber Drives

Veritas Terms and Definitions

December 3rd, 2008 No comments

Term & Definition

Disk group:
Collection of data, volumes, and associated parts (subdisks, plexes, and vmdisks).

Virtual partition on which filesystems are created or databases operate.

Data plex:
1 copy of the data.

Log plex:
Logging information for volumes (RAID 5 or DRL). Displayed with a double border.

Contiguous regions on a disk. 4096 is the limit on the number of subdisks per physical volume.

VM Disks:
Public region of a physical disk.

Merging Fiber Channel Fabrics

December 3rd, 2008 No comments

You have two fabrics running off of two switches. You’d like to make them one fabric. How to do that? For the most part, it’s simply connecting the two switches via e_ports.

Before doing that, however, realize there’s several factors that can prevent them from merging

1. Incompatible operating parameters such as RA_TOV and ED_TOV
2. Duplicate domain IDs.
3. Incompatible zoning configurations
4. No principal switch (priority set to 255 on all switches)
5. No response from the switch (hello sent every 30 seconds)

To avoid the issues above:

1. Check IPs on all Service Processors and switches; deconflict as necessary.
2. Ensure that all switches have unique domain ids.
3. Ensure that operating parameters are the same.
4. Ensure there aren’t any zoning conflicts in the fabric (port zones, etc).

Once that’s done:

1. Physically link the switches
2. View the active zone set to ensure the merge happens.
3. Save the active zone set
4. Activate the new zone set.