NAS and SAN Introduction
1. When Eli says that NAS is 'basically' a shared file server, what does he mean? How does a NAS differ from a conventional file server?He means they share file data on a network similar to a share file server though a NAS only stores data. A NAS only has application like the conventional file server.
2. ccording to Eli, what is the problem with serving files from a conventional Windows File Server?
The problem with serving files from a conventional Windows File Server is users can browse the Internet and download. Not possible on a NAS
3. How does Eli define a SAN?
A SAN is network of boxes to store data.
4. In a SAN context, what is a cluster? What are the inherent advantages of a cluster?
A cluster is a SAN context allows creates replication and when a SAN fails another SAN can still provide data. Replication and redundancy are the inherent advantages of a cluster.
5. From Eli's perspective, what is the most obnoxious problem with commercial storage? The most obnoxious problem with commercial storage is acquiring a hard drive. Hard drives are huge and require space to be stored and fill out quickly. Enterprises are then required to migrate data and add hard drives.
6. From Eli's perspective, what is the advantage of storing a VM instance on a SA and running the instance on a hypervisor?
The advantage is that the VM instances are stored on the SAN and not on the physical machine. This creates redundancy and fail safes.
7. From Eli's perspective, what is the major advantage and disadvantage of Fiber Channel?
The major disadvantage of Fiber Channel is very expensive. The advantage is the speed.
8. How does Eli describe iSCSI?
iSCSI is the "poor mans" version of Fiber Channel for connecting SANs.
Introduction to RAID
1. From a computer's perspective, what does RAID do?A computer perceives RAID as one hard drive when it can actually be many.
2. What is the advantage of disk striping?
The advantage of disk striping is that it allows faster reading and writing on hard drives.
3. What is the main disadvantage of disk striping?
The main disadvantage of disk striping is that data is spread among several disks, which can allow for one failure to corrupt data.
4. What is the main advantage and disadvantage of disk mirroring?
Disk mirroring is when data written on one hard drive it is automatically written to the other. This process provides redundancy in the event that one disk fails. The disadvantage is that the user only had the available space of one hard drive disk instead of all disks and the speed is not faster because of two hard drives.
5. What is the major advantage of RAID 5?
The major advantage of RAID 5 is that it includes disk striping and also redundancy by creating duplicates of disks.
6. In a RAID 5 context, what does hot swappable mean?
Hot swappable means hard drives can be removed while the company system is running or means that a drive replaced without powering down the system.
7. What are the 3 most common RAID configurations?
The 3 most common RAID configurations are RAID 0, RAID 1, and RAID 5.
Introduction to Solid State Drives (SSD)
1. What is the usual bottleneck for a computer?Hard drives are the usual bottleneck for a computer.
2. Do solid state drives wear out in normal usage? Is this relevant?
Solid state drives do wear out in normal usage over time. It should not matter for most standard users as other hardware will be replaced before an SSD. In data centers however, it is significantly more important to consider whether hardware may be replaced before the SSD.
3. In terms of MTBF how long to SSDs last compared to platter based HDs?
Solid state drives last twice as long as platter based hard drives.
