RAID

RAID (redundant array of independent disks) is a data storage virtualization technology that combines multiple physical disk drive components into a single logical unit for the purposes of data redundancy, performance improvement, or both. Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of redundancy and performance. The different schemas, or data distribution layouts, are named by the word RAID followed by a number (e.g. RAID 5, RAID 6, etc.).

RAID 5

This raid level is like RAID 6 but it will calculate the checksum once. So the read times are similar but the write times are much faster. This raid level is used for most items. VM storage, latency sensitive file servers, and other needs where the read is important but the write also has some requirements.

RAID 6

This raid level is very similar to Raid 5. It places your data across a number of disks and then uses a couple of other disks to write a calculation known as a checksum. The checksum enables the system to recover the data on a disk that is lost. For instance if you had a 6 disk raid 6 you would use 4 of the disks to store data and the final 2 disks would be used for the checksum. This one is the slowest write raid type but it has pretty good read times. When you go to read data from the disks it can read from all 6 disks but when you go to write the system has to calculate the checksum twice before writing to disk. Thus making writes much slower. For this raid type because it is slower it is also cheaper. So many customers use this for long term file storage or file servers. Sometimes the backup drive of a SQL server because the read/write times are not important.

RAID 10

This raid level is geared to reading and writing intensive applications. It is used for work loads that do mainly writes like SQL databases. This one will write the data to half of the disks and then make a copy of that data to the other half of the disks. It can read from all of the disks and when it writes it can write to half of the disks but it does not do any checksums the data just goes straight to disk since the other half of the disks are a mirror copy. This one is by far the most expensive due to the loss of half the needed drives. But this one is very useful and popular with the applications that are intensive read/writes. For instance SQL server for databases, log files, and the tempdb.

24kw
per "u"
shared ASA
IPS,IDS
Managed Cabinets + Shared Cabinets
IPv4 vs IPv6
Norse
NOC: Network Operating Center
Dynamic Density Control
Class C
DAG,Database Availability Group
GTM,Global Traffic Manager
Private Transport Ring
VDI

Glossary

Helpful URL's