EMC VMAX-3 series systems were launced almost an year back, and more and more customers are going for VMAX-3 now. From an administration perspective there are few differences with VMAX-3 from the previous VMAX series.
You may read the architectural differences in my previous posts on VMAX-3 series. Let’s discuss some of the most important things to be taken into consideration while creating new devices with the new product series..
No Thick devices:
VMAX-3 series does not support thick devices. All devices are thin devices and space will only be allocated when the system start writing data into it. And the thin device extent is 128KB (improved granularity from 768KB in previous models).
No Meta :
VMAX-3 series does not support meta device creation. With the maximum size of single device support in TBs (240GB is the max size of a single device in VMAX 2nd gen), there’s no need of a meta creation.. 🙂
As meta is not supported, auto meta feature also is not available with VMAX-3 series. You will find N/A for the auto meta feature in symcfg list -v output instead of enabled/disabled.
Increased track size :
VMAX-3 now have a track size of 128KB. It is now doubled from 64KB (1 track = 64KB with the previous generation of VMAX systems) and hence a Cylinder in VMAX-3 is 1920 KB (With VMAX series it was 960KB). This is very much important to remember this during device creations.
More in coming posts… Your thoughts in comments. Thanks.
Hi Vipin,
Appreciate your time in posting a lot valuable information in your blog!!
Coming to this post, as you have mentioned below as:
“And the thin device extent is 128KB (improved granularity from 768KB in previous models).”
If i’m not wrong, as per the calculation i know, 1 extent = 12 Tracks and each track in VMAX earlier generations is 64 KB(8 sectors, 1 sector=8KB), so it comes in total 1 extent size= 12*64 KB = 768 KB which you have mentioned is correct for the older VMAXs models BUT
Since the VMAX3 has an increased track size which is 1 track=128 KB(16 sectors, 1 sector=8KB),
as per the extent calculation above, 1 extent size = 12 tracks = 12*128 KB = 1536 KB.
Is my assumption correct!!!
Hi Vijay,
Thanks for your note.
Coming to your query, you are right that the track size is now 128KB (not 64KB) with VMAX-3. But the extent size is still 128KB as the allocation unit is 1 track only with VMAX-3 series systems.
You may refer the page 9-10 in VMAX-3 new features for further clarification.
Regards,
Vipin V.K
Thanks for correcting me Vipin!! You are absolutely correct.
VMAX3 looks very robust in terms of capacity utilization and offering a great application level performance.
Really appreciate your efforts in bringing these major differences between the next gen VMAX array code features