LUN Masking vs LUN mapping

Again this is a great googly questions that Interviewer ask : What is the difference between LUN mapping and LUN masking:


LUN Mapping:

The name itself speak to map a LUN to the Host (server). In SAN environment,
there are series of steps to be performed before any LUN mapping can be done to the Host

Requirement for LUN mapping:

• Initiator WWN (World Wide Name)
• Target WWN
• Zoning 

Initiator: Initiator is itself a hard coded 64 bit digit embedded on HBA (host bus adapter). Think of this like a MAC address in TCP/IP scenario. It is unique for every HBA. Initiator is always on Host (server).

Below indicates here in below picture each HBA card connected to Fibre Channel

Here you can see clearly that there are 2 HBA cards and in each card there are two HBA ports. 

Target: Target is usually on Storage side, the target is a port on storage side 

After you have WWN of both 1. Initiator and 2. Target
Now you have to zone it unless at the Storage end you will not able to see the Hosts and will not able to Map.

I will discuss Zoning in different post.
Zoning is done on fabric switch which binds the Initiator to the target


LUN Masking:

LUN masking is more in security of the data meaning it Masks the LUN (Logical Unit Number) from the Host which is not meant for.
Eg:
Suppose I have 2 Hosts A & B and 4 LUNs named LUN1 to LUN 4
2 LUN's (LUN 1 and LUN 2)are mapped to one host which is a windows Host and other 2 LUN's are mapped to Host B which is a Linux Host. 
Now due to Data Confidentiality you don't want that Host A should see the LUN 3 and LUN 4 so restricting the access to Host A. 

Add caption

SAN vs NAS

A great big question for an interviewer for which you can take half an hour to explain the things to the interviewer.

It simply depends on your expertise level and exposure to this field,that how you going to tackle this question. :P

SAN (Storage Area Network)

• Its a technology which uses FC( Fibre Channel) to map a Host to the Storage Array. 
• It uses a Block Level architecture
• Most used protocol used in SAN are FCP ,iSCSI , FCoE (Fibre Channel over Ethernet)

SAN Hardware requirement :

1. Host with Host Bus Adapter (HBA)
2. Fabric Switches or SAN switch
3. FC cable (throughput is around 8Gbps)
4. Storage Array 

SAN is far more costlier than NAS to implement. 

Topology of SAN:

NAS (Network-Attached Storage)

• NAS will be using an Ethernet connection for sharing files over the network. The NAS device will have an IP address, and then will be accessible over the network through that IP address. Eg :When you access files on a file server on your windows system, its basically NAS.
• NAS uses File-Level Architecture 
• Protocols used here are NFS/CIFS and SMB

NAS Hardware requirement :

1. Ethernet cables
2. Standard switch/Hub (TCP/IP)
3. NAS server (can be a Windows server which is hosting a NAS file share)

Topology of NAS:

For more details regarding Block and File-level Storage visit:

http://cloud-stuff.blogspot.in/2016/06/block-vs-file-storage.html

Block vs File Storage

One should always keep the primary difference between these two,however i have listed little more about both.Have a look :)

File Level Storage - This storage technology is most commonly used for storage systems, which is found in hard drives, NAS systems and so on. In this File Level storage, the storage disk is configured with a protocol such as NFS or SMB/CIFS and the files are stored and accessed from it in bulk.

• The File level storage is simple to use and implement.
• It stores files and folders and the visibility is the same to the clients accessing and to the system which stores it.
• This level storage is inexpensive to be maintained, when it is compared to its counterpart i.e. block level storage.
• Network attached storage systems usually depend on this file level storage.
• File level storage can handle access control, integrate integration with corporate directories; and so on.
• "Scale Out NAS" is a type of File level storage that incorporates a distributed file system that can scale a single volume with a single namespace across many nodes. Scale Out NAS File level storage solutions can scale up to several petabytes all while handling thousands of clients. As capacity is scaled out, performance is scaled up.

Block Level Storage - In this block level storage, raw volumes of storage are created and each block can be controlled as an individual hard drive. These Blocks are controlled by server based operating systems and each block can be individually formatted with the required file system.

• Block level storage is usually deployed in SAN or storage area network environment.
• This level of storage offers boot-up of systems which are connected to them.
• Block level storage can be used to store files and can work as storage for special applications like databases, Virtual machine file systems and so on.
• Block level storage data transportation is much efficient and reliable.
• Block level storage supports individual formatting of file systems like NFS, NTFS or SMB (Windows) or VMFS (VMware) which are required by the applications.
• Each storage volume can be treated as an independent disk drive and it can be controlled by external server operating system.
• Block level storage uses iSCSI and FCoE protocols for data transfer as SCSI commands act as communication interface in between the initiator and the target.

Fast VP vs Fast Cache

I saw many interviews that ask this question - whats the difference between Fast VP and Fast Cache?

FAST Cache:

A FAST Cache is literally a High Speed Disks which acts a Cache Disk in EMC Storages. Basically it's a Flash Disk, which you can combine together through a small wizard via Unisphere and can configure the FAST cache. 

The basic purpose of FAST cache is to deliver the most HOT data at an instant or we can say that the data which is most hit on any LUN gets transfer to the FAST cache and hence the data get accessed from there, delivering more IOPS.


NOTE- These are a combination of Disk of same type flash Disk SSD which are basically SLC type

FAST VP:

Fast VP is a  Group of Disk (may consist of different type of SSD's like Flash,SAS,NL-SAS) to create a Storage Pool and the HOT data is moved across the disks after analysis over a period of time.


Think like this 

4 Flash SSD + 4 SAS + 2 NL-SAS = Extreme Performance (pool)
4 Flash SSD + 2 SAS + 2 NL-SAS = Balanced Performance (pool)
1 Flash SSD + 2 SAS + 4 NL-SAS = Capacity Performance (pool)

It allows you to create multiple storage Pools so that you can get the maximum out of any SSD and also the most frequent data after analysis moved to Flash disk. 

NOTE- FAST VP Flash SSD's are eMLC's,they cannot sustain high IOPS hence cannot be used as FAST Cache disks


Difference between FAST CACHE and FAST VP

FAST CACHE	FAST VP
Allows Flash drives to be used to extend the existing caching capacity of the whole storage system	Allows a single LUN to leverage the advantages of multiple drive types through the use of storage pools.
Granularity is 64 KB	Granularity is 1 GB
Data that is accessed frequently is copied from HDDs to Flash drives	Data is moved between different storage tiers based on statistics collected over a period of time
Use when workload changes are unpredictable and very dynamic, and require a quick response time	Use when workload pattern changes are predictable and relatively low.
Constantly promotes frequently accessed HDD data to FAST Cache. There are no relocation cycles.	Data movement occurs in scheduled or manually invoked relocation windows
Calculation to decide which data needs to be promoted to FAST Cache is performed continuously.	Calculation to decide which portion of data need to be moved is performed once every hour.

If you want more indepth details you can refer to below link:

http://tinyurl.com/zn9h7vq

Let me know if you have any Questions.. Happy reading

Avamar Plugin for vCloud Director

Hi Guys, this is my first blog ad I am here to discuss Stuffs which are related to cloud. I will not go very Horizontal with the term "CLOUD",but i wish people or juniors who just made an entry to the world of cloud will find it helpful.
We can discuss any topic related to Storage and Backup and hopefully i will be able to answer them as precise and concise as you want them :)
Vmware and windows administration will also go hand in hand but i want my blog to get sweet by the Term "Storage and Backups"

Recently I went through the integration of Avamar Plugin with vCD which was painful for me as the EMC document doesn't provide enough details which was a complete chaos to me. later i find myself in a Do or Die situation. 

What is Avamar Plugin all about??

A avamar plugin is a plugin which lets you to take a backup of vApp. vApp once created on vCloud Director, you can schedule the backup of the vApp from the VCP UI server (Just an Interface). 
There are several requirement that needs to be fulfilled before deploying this plugin like ports ,network etc etc.

You can download the Pdf from the Tinyurl 
http://tinyurl.com/hu7jwz8

Let me know if you face any difficulty while deploying.Happy to help :)