It depends on you IO workload. I have a high IO 10TB SAP SQL DB with 24 datafiles/LUNs that has a maximum IO/s around 16K. We built it this way from a SAP recomendation, they recomend one datafile per LUN per CPU/core. If it's a low IO DB a couple large LUNs should work.
first of all, symmetrix has maximum meta LUNlimitation, 16TB for Vmax, 8TB for dmx3&4, and 4TB for dmx1&2. So if your SQL database is larger than symm max LUN size, you have to use multiple LUNs.
second, if there is MSCS environment, it doesn't support volume set, then you can't use multiple LUNs for a single file system.
If you are not hit by above limitations, then your question turns into "host side string or Symmetrix side string" choice.
The answer is: it depends.
We mostly don't like to configure LUNs in its maximum size. there are always many reasons to make such limits (maximum size). Performance is most likely the reason.
So finally you may have to configure several not huge meta luns, and make volumes sets over them. If these is MSCS environment, you have to build a LUN as large as you required but it couldn't exceed Symmetrix limitation.
HankD1
20 Posts
1
February 24th, 2011 13:00
It depends on you IO workload. I have a high IO 10TB SAP SQL DB with 24 datafiles/LUNs that has a maximum IO/s around 16K. We built it this way from a SAP recomendation, they recomend one datafile per LUN per CPU/core. If it's a low IO DB a couple large LUNs should work.
Jianyun_e442cb
56 Posts
1
February 24th, 2011 23:00
first of all, symmetrix has maximum meta LUNlimitation, 16TB for Vmax, 8TB for dmx3&4, and 4TB for dmx1&2. So if your SQL database is larger than symm max LUN size, you have to use multiple LUNs.
second, if there is MSCS environment, it doesn't support volume set, then you can't use multiple LUNs for a single file system.
If you are not hit by above limitations, then your question turns into "host side string or Symmetrix side string" choice.
The answer is: it depends.
We mostly don't like to configure LUNs in its maximum size. there are always many reasons to make such limits (maximum size). Performance is most likely the reason.
So finally you may have to configure several not huge meta luns, and make volumes sets over them. If these is MSCS environment, you have to build a LUN as large as you required but it couldn't exceed Symmetrix limitation.