Preparing for excam: Questions about ISMV2

Dear Raid-Zero

Sorry for my delayed answer but i've been to holidays the last few days (yay)! Thank you very much for this detailed explanation which made me clear about the differences.

Well I have to further question which you may be able to answer:

1) When WWN zoning are we going to use the WWNN or the WWPN to zone? I always used the WWPN but in the book they are talking about to use the WWNN of the HBA which is in my opinion wrong (imagine a dual port HBA).

2) I wanted to implement a mixed pool  based on 20x 15K 300 Gbyte SAS disks and 10x 900 Gbyte SAS Disks and turn on FastVP but during creation it tells me that it is not possible to use same disk with different sizes and tiering will not be able until i add different disks. Well for me 10k and 15k disks are not the same but it seems it takes the interace (FC, SAS, NLSAS) as a reference about what is fast and what's not. Is it true that the rpm is not counted for this and it's only the type of interface? Is there a matrix to see what is NLSAS, SAS and FC?

2.1) Is Flash Disk considered as SAS or FC or something own?

Thank you so much and best regards,

Michael

1. When zoning you always use WWPN, never the WWNN.  If ANY resource directs you to use WWNN it is either incorrect, or a typo/misprint.  Use WWPN for the reason you state - multiple ports can share WWNNs.

2. For FAST VP purposes the tiers are Extreme Performance (Flash and Flash VP drives), Performance (all SAS), and Capacity (all NLSAS).  Each tier should have a single type (speed and size) of drive in it.  Spindle speed and capacity aren't differentiators between SAS drives as they occupy the same tier on the VNX, hence you can't mix them in the same pool.  FC disks used to be in the Performance tier along with SAS but they haven't had FC drives for a while - since Clariion, though those systems are definitely still alive out there.  Now it is all SAS. 

2.1. Flash or EFD is its own thing in the Extreme Performance tier.  If you look in the disk list you'll see these sometimes listed as SAS Flash or SATA Flash or something else - these are all the same.  Just be aware that on VNX2 there are two kinds of flash drives - Flash and Flash VP.

- Flash, or regular EFD, are SLC drives and are intended for FAST cache, but can also be used in pools. 

- Flash VP, or EFD VP, are eMLC drives and are intended for pools - these may not be used for FAST cache. 

The drives can be mixed in pools, but may not be mixed in the same RAID group (so I can't have 3 EFD and 2 EFD VP drives in the same RAID 5 4+1) and won't hot spare for each other.  As a rule, I wouldn't recommend mixing them in the same pool (or generally use FAST Cache drives in pools) unless I had a really compelling reason for doing it. 

Hi Raid

I really appreciate your effort that is amazing it's great to learn stuff in that way. I hope I do not bother you with such silly questions.

Best regards

Further one =) LUN maskis is like zoning a security approach and I did it many times. But is LUN masking based on the WWN of the Hosts, the name or the FC channel address or even the mapped port?

Within the GUI i craete a storage group and add hosts and LUNs. What is it considering? Is there a way of saying access to everyone like zoning?

Hi

Another maybe easy one =)) iSCSI ports on EMC Storage Systems are they dedicated iSCSI HBAs or usual NICs with Software iSCSI Initiator?

Thank you :-)

Hi Duker,

LUN Masking is a process, which defines that which LUNs a host can access. This ensures that LUN access by host is controlled appropriately, preventing unauthorized or accidental use in a shared environment.

          For eg: Consider a storage array with two LUNs that store the data of the sales and finance departments. Without LUN masking, both departments can easily see and modify each others data, posing a high risk to data integrity and security. With LUN masking, LUNs are accessible only to the designated Hosts.

Please note that storage array is always iSCSI target. Host will be always iSCSI initiator. Host can use a normal NIC card with iSCSI initiator, a TOE (TCP Offload Engine) or a dedicated  iSCSI HBA. 

Hi $ree

I do understand the idea behind LUN Masking but i am  intrested into how or what is taking into consideration to give access to hosts. Hostname, IP, WWN of the initators which are assigned to a host?

I assume that there is a ACL which contains system LUN IDs and the appropriate host initiators WWNs? Am I right?

Thank you anyway =)

Hi Duker,

I hope you have already done LUN masking many times. Once we completed the zoning of host HBA with SPs, we will be able to see the host wwn under initiators/Connectivity status tab. While registering the initiators (WWN), we are specifying the host name and IP address. While doing the LUN masking, we will be assigning the LUN to this particular host. While registering the host itself we are using host name, IP and wwn.

So the dedicated iSCSI Targets (EMC Modules) are HBAs, TOE or Software iSCSI? Or is there no such difference for target adapters?

Thank you

The only difference between, traditional, Thin and thick Lun is

Traditional Luns are carved from raid group, However thin and thick are carved from storage pool.

Hi Duker,

Normally in EMC storages, iSCSI ports (1GB and 10GB) will be coming with RJ-45 ports. 10GB/s FCoE ports will come with specific type of SFP module.

You can generate Hardware overview document for VNX arrays from EMC my document site (Select learn about VNX hardware option under about VNX). It will be having the diagrams as well. below is the link.

https://mydocuments.emc.com/index.jsp

What is the meaning of RAID 5 (4+1)?

in R5 we need minimum 3 disk out of which one is parity,

can it be 5 for data and 2 for parity,

Please explain!!

Hi Friends,

If I am putting comments, it is going for moderator approval. Any Idea why it is like that

2 for parity is called RAID 6, f.e. 6+2 or 12+2

1 for parity is called RAID 5, f.e. 4+1, 8+1 ...