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Preparing for excam: Questions about ISMV2
Hey there
right know I am studying for the ITSMv2 Excam and I am reading the book about it. On page 82 there is a chapter about traditional LUNs and thin LUNs.
Traditional thick LUNs are mapped to a traditional RAID Group and expanding those would be a MetaLUN. So far I've no issue with that BUT
beased on the book a Thin LUN resides in a Shared Pool. But from my experience with working on EMC VNX i can create a traditional tick LUN in the pool as well and expand it with capacity out of the pool. If i want to use Thin i can say this is a Thin LUN by klicking "Thin" and allocated 10 TB even if i am using only 2 TB. Am I right? Or am I wrong? Are all LUNs in a pool Thin LUNs even when "Thin" is not ticked? Can i change a LUN in a pool to thin and thick all the time? Are there two meanings of thin in EMC environments?
Thank you for clarification and greetings,
DukeR1337
208 Posts
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August 25th, 2015 06:00
And finally the last bunch of questions =D
So that's it so far! Thank you so much guys, really appreciate your effort to share your know how.
Cheers,
Duke
DukeR1337
208 Posts
0
September 3rd, 2015 05:00
Hi guys
I am in the end phase of preparing! Soon I am going to take the excam. I found a lot of questions, white papers, blue prints etc. etc.
I've only difficulties with one type of question, it is about the follwing.:
A department in an rganization requires 300 GBN of storage space for business application. The production LUN is RAID 1+0 protected and has both a local and a remote replica. Rhe local replica is a RAID 1 LUN and the remote replica is on a fice disk RAID5 LUN.
If the raw disk storage costs per GB is 3 dollar, what is the charback cost to the department for applicaiton storage?
I've calucalted the following:
It's a RAID 1 + 0 so first mirrored then striped
R0= R1(150+150) + R1(150+150 GB) = 600 GB
Plus R1 300GB + 300 GByte Local replica = 600 GB
Plus R5 300 Gbyte = 300 GB
Overall 1500 GByte Space consumption * 3 Dollar each = 4500 Dollar
But the right answer seems to b e 4725$
I really dont get it...
1) Is my assumption correct that i dont need 300 GByte disk within RAID 1+0 because striping i can use 2x 150 resp 4x
2) where is my bug? When i take 4725$ and device it with 3 dollars it gives me an GB amount of 75GB so where is this coming from?
Thank you so much
Rainer_EMC
8.6K Posts
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September 3rd, 2015 06:00
Hint: how are you able to provide R5 protection without using capacity for parity ?
Peter_EMC
674 Posts
1
September 3rd, 2015 06:00
> Plus R5 300 Gbyte = 300 GB
you are missing the parity of Raid5
Raid 5 on 5 disks (4+1)
300 GB (data) + 75 GB (parity) = 375 GB
So in sum it is 600 + 600 + 375 = 1575 GB * 3 $ = 4725$
StorageShray
26 Posts
0
September 4th, 2015 04:00
Good day all,
Please explain FAST VP and FAST Cache,
Also, FAST in terms of both.
Thanks
brettesinclair
2 Intern
2 Intern
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715 Posts
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September 4th, 2015 06:00
Some light reading;
https://support.emc.com/docu48729_FAST-Cache-and-FAST-VP-for-VNX-OE-for-Block-5.33.000.5.015-Release-Notes-.pdf?language…
Rainer_EMC
8.6K Posts
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September 4th, 2015 06:00
FAST VP = automatic movement of blocks between differents tier disks in a pool
FastCache = caching of frequently used blocks on flash drives
You will find the more explanations in the VNX white papers – available from support.emc.com or emc.com
https://store.emc.com/gb/Solve-For/STORAGE-PRODUCTS/VNX5200/p/VNX-VNX5200-storage-platform?PID=EMC_PRD-VNX5200-BB7D_SPLSH#Learn
Rainer_EMC
8.6K Posts
0
September 4th, 2015 08:00
I would rather suggest the white paper than the release notes.
If the FAST VP and Fast Cache white papers are too deep then there is also the introduction to the VNX white paper.
Anonymous
5 Practitioner
5 Practitioner
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274.2K Posts
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September 4th, 2015 09:00
FAST (Fully Automated Storage Tiering) contains two types of features. But both
These features included in FAST Suite license in VNXe and VNX platforms.
1. FAST Cache
FAST Cache means you can extend the cache by adding SSD in VNXe and VNX platforms. FAST Cache improves performance in terms if IOPS since per SSD IOPS count is high. When you enable tiering and activate FAST Cache feature for that particular LUN hot data will be migrated to FAST Cache with 64kb data chunks. There is a maximum limit you can extend the FAST Cache for each platform. Recommended RAID is to go with RAID 10 for FAST Cache.
2. FAST VP
FAST VP means FAST Virtual Provisioning which enable auto tiering for LUNs that extended to more than one disk type. Disk types are SSD, SAS and NLSAS. Enabling FAST VP you can move data between different disk tiers (from NL-SAS To SSD and from SSD to NL-SAS). This gives better performance when required by upgrading hot blocks to high performance tier. Here the moving block size is 256MB.
These features are Fully automated and EMC storage is intelligent enough to identify when to upgrade and when to downgrade the data between tiers. There is no manual intervention to move data between tiers.
Regards,
Rishan.
+9477 00 52 522
Sent from my iPhone
brettesinclair
2 Intern
2 Intern
•
715 Posts
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September 5th, 2015 02:00
If someone has no concept of the features like the poster, the Release notes I linked have an excellent "Product Description" for both features/products beginning on Page 2. It summarises them very nicely without going into too much depth, all in just a few paragraphs. They are well written.
Of course, further info and technical details can be garnered from the White Papers.
DukeR1337
208 Posts
0
September 7th, 2015 07:00
Hi
while i was writing my question about this resp. about my confusion I realised that I have to calucalte 300 GByte / 4 * 5 to get the parity or the whole amount. Jesus... sometimes I am a little dum****
Thanks =)
DukeR1337
208 Posts
0
September 16th, 2015 06:00
Hey guys
I just would like to let you know that I've passed the excam with excellent score! Well this is your earnings as well, I really would like to thank you all for your help!
Cheers
PS: Right now I am studying for the Implementation Engineer Exper Excam for VNX, so be prepared
PPS: IN addition can you have a look at those questions which have not been answered yet?
And finally the last bunch of questions =D
So that's it so far! Thank you so much guys, really appreciate your effort to share your know how.
Cheers,
Duke