Server+ Cram Notes

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Server+ Cram Notes

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1 About These Cram Notes
2 Quick Reference Sheet: Cram Notes
3 Uninterruptible Power Supply
4 NAS v SAN
5 Memory
6 iSCSI & FCIP
7 CPU's
8 OS's
9 Tips from members who have taken the Server + exam

[edit section] About These Cram Notes

This page contains a bulleted list of short points that you must know for the Server+ exam. Please avoid long explanations and list on only key points. You can make bullet lists with "*".

* First level list object
** Second level list object
*** Third level list object
* Another first level list object

In general use half the words you would normally use and keep points short.

NOTE: Thank you sid316 for your contribution to this page and helping build it.

[edit section] Quick Reference Sheet: Cram Notes

RAID
- Stands for Redundant Array of Independent (or Inexpensive) Disks
- Benefits: fault tolerance
- Disk Mirroring: One disk duplicates another disk.
- Disk Striping: The data is spread out over multiple disks.
- Parity: Is what the raid controller uses to rebuild the data incase of a disk failure.
RAID Levels
- RAID 0 - Disk Striping w/ no parity. Need at least 2 Disks
  - RAID 0 - No Fault Tolerence.
- RAID 1 - Disk Mirroring. Need at least 2 Disks.
- RAID 5 - Disk Striping w/ parity. Need at least 3 Disks.
  - Raid 5 - Most Widely used.
- RAID 0+1 - Disk Striping + Disk Mirroring.
  - RAID 0+1 - For every disk striping, need to be one mirroring it.
    - RAID 0+1 - 2 Disk Striping = 2 Disk Mirroring. 1:1 Ratio
SCSI List - Quick Reference
- 1.SCSI - 5MB @ 8bits
  - 2. Wide SCSI - 10MB @ 16bits
  - 2. Fast SCSI - 10MB @ 8bits
  - 2. Fast Wide SCSI - 20MB @ 16bits
    - 3. Ultra SCSI - 20MB @ 8bits
    - 3. Wide Ultra SCSI - 40MB @ 16bits
    - 3. Ultra2 SCSI - 40MB @ 8bits
    - 3. Wide Ultra2 SCSI - 80MB @ 16bits
    - 3. Ultra3 SCSI - 160MB @ 16bits

SCSI Signaling - The manner that a SCSI interface sends signal down the cable.
- 3 Types - Single End, High Voltage Difference & Low Voltage Difference
  - Single End - Drives signal down the cable along with the ground.
    - SE - 5mz @ 6m
    - SE - 10mz @ 3m
    - SE - 20mz @ 1.5m
      - Problem - SE is susceptible to noise interference.
  - High Voltage Difference - Drives the signal down 2 lines, one being the inverse of the other. The difference of the two lines is the signal.
    - HVD - 25m
      - Problem - More Expensive than SE
  - Lov Voltage Difference - Very similar to HVD except the voltage and current are lower.
    - LVD - 12m
    - Advantage - Low properties make it cheaper than HVD.

[edit section] Uninterruptible Power Supply

UPS Rating = Volt-Ampere or Watts
- VA = Watts x 1.67 or Watts = VA x .60
Total VA of all the connected must not exceed the UPS.
- The VA of the UPS should be 20 to 25% greater.
Two Categories: Online & Offline Power Supply
- While the utility power is normal:
  - Online Power Supply - The equipment run off the battery.
  - Offline Power Supply (Standyby) - The connected equipment run off the utility power.
- When the utility power goes out:
  - Online Power Supply - equipment continue to run on battery and experience no switch over time.
  - Offline Power Supply - The ups inverter switches to the battery. This is called switch over.
    - Switch over time is measure in (MS). It is said that a PC can go as high as 100ms.

[edit section] NAS v SAN

Network Attached Storage (NAS)
Name given to a dedicated storage unit that can be directly attached to the network.

Characteristics
Transfers data as files.
Transfers files over local area network. (i.e. ethernet, wireless, fiber)

Storage Area Network (SAN)
Is a network that is consists of storage units.

Characteristics
Transfers data as blocks.
Transfers blocks over wide area network using FCIP or iSCSI media.