Larry,
1) My current SSD are ES0H, announced November 2013 - IBM i 7.1 Technology Refresh 7 and IBM i 6.1 Additional Enhancements.
The documentation doesn't always include if they are 5XX or 4K.
How does one determine this?
I'm using FC #5913, so from your note below, concluding they are 5XX.
775 GB SFF SSD with eMLC (#ES0E, #ES0F, #ES0G, #ES0H)
The new 775 GB SFF SSD, using the same technology as the new higher performance 387 GB disk drive, doubles the capacity that can fit in a single slot. IBM i support is provided for both POWER7 and POWER7+ servers, and for both IBM i 7.1 and IBM i 6.1 with 6.1.1 machine code.
2) Will these disks work on Power8 in an EXP24S, or future Power9 with an EXP24S.
3) Base on your note, (4K Disks they are better because they cut the number of I/Os by 8) for future planning, get rid of the 5XX and plan on using 4K.
4) With that said, future planning for disks.
Production - for top performance
#ES8D - 775GB SFF-2 SSD 4k eMLC4 for IBM i
#ES8G - 1.55TB SFF-2 SSD 4k eMLC4 for IBM i
#ES8R - 775GB SFF-3 SSD 4k eMLC4 for IBM i
#ES8W - 1.55TB SFF-3 SSD 4k eMLC4 for IBM i
R&D - improvement over current 10K spinny, but using the cheaper SSD.
#ES84 - 931 GB Mainstream SAS 4k SFF-3 SSD for IBM i
#ES8Z - 931 GB Mainstream SAS 4k SFF-2 SSD for IBM i
#ES93 - 1.86 TB Mainstream SAS 4k SFF-3 SSD for IBM i
#ES97 - 1.86 TB Mainstream SAS 4k SFF-2 SSD for IBM i
#ESE2 - 3.72 TB Mainstream SAS 4k SFF-3 SSD for IBM i
#ESE8 - 3.72 TB Mainstream SAS 4k SFF-2 SSD for IBM i
5) However - I did read this link that scares me a bit with the performance of large SSD drives, especially if they are Mainstream.
An interesting question about SSD performance scaling with size
https://www.ibm.com/developerworks/community/blogs/svcstorwize/entry/An_interesting_question_about_SSD_performance_scaling_with_size?lang=en
Any thoughts from the group?
Paul
-----Original Message-----
From: DrFranken [mailto:midrange@xxxxxxxxxxxx]
Sent: Monday, December 04, 2017 5:42 PM
To: Midrange Systems Technical Discussion; Steinmetz, Paul
Subject: Re: Power7 / Power8 internal disk differences
Yes and no.
Physically the disks in the Power7 CEC are in slightly deeper and slightly taller sleds than those in Power8 CEC disks. However the disks could be resleded and used in the new system as the actual disks themselves are compatible.
As for the 4K Disks they are better because they cut the number of I/Os by 8. Now IBM i has used 4K has a block size since the CISCO to RISC migration years ago but has always had to write 8 520Byte sectors to handle that. (Whether they only update 1 of the 8 if a very small update is performed within the block I do not know.)
Tracking what needs to be updated should be simpler with 4K Block disks and they are pretty much the standard in the industry now. With them you can address 8 times the storage that you could with 520 byte sectors using the same number of addresses.
To use 4K Block disks you need PCIe Gen3 RAID cards or newer on Power Systems. So for example FC #5913 or FC #ESA3 controllers will NOT recognize 4K Disks. FC #5887 disk drawers work fine with either 4K or
520 byte disks.
Power8 CECs can have 520 or 4K Block disks in them.
- Larry "DrFranken" Bolhuis
www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.
On 12/4/2017 4:47 PM, Steinmetz, Paul wrote:
1) Are Power7 and Power8 internal disks different?
2) What is difference between the 5XX and 4k disks, which is better, and where are they used?
https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki
/IBM%20i%20Technology%20Updates/page/IBM%20i%20IO%20Support%20Details
Thank You
_____
Paul Steinmetz
IBM i Systems Administrator
Pencor Services, Inc.
462 Delaware Ave
Palmerton Pa 18071
610-826-9117 work
610-826-9188 fax
610-349-0913 cell
610-377-6012 home
psteinmetz@xxxxxxxxxx
http://www.pencor.com/
midrange.com
