>>> On 6/26/2009 at  8:31 AM, "Burton, Randy" <[email protected]> wrote: 
-snip-
> I agree - and I'm curious about what people are doing with "standard"
> file system layouts for zLinux - are most people doing something similar
> to this:
> 
> Disk 1:       all the system stuff, on 390 disk:
-snip-
> 
> Disk 2:       standard "data" kind of stuff, also on 390 disk:
-snip-
> 
> Disk 3:       /swap (also on 390 disk)
> 
> Disk 4:       /data  (all the really big stuff goes here, on FCP)

I'm actually seeing some customers that _only_ have SCSI over FCP systems.  
They're relatively new mainframe shops, and so don't have a huge investment in 
ECKD emulation and FICON.  From my perspective, that makes things a little bit 
more tricky than otherwise, but not prohibitively so.

The amount of performance-related data that is available for SCSI over FCP is 
improving over time, but from what I understand, it still lags behind FICON 
devices.  So, when it's working well, you get better performance, but when it's 
not working well, it's harder to figure out why.  So, like most things in IT 
and life, it's a tradeoff at least for now.

What I usually recommend to people is, whatever the source of your disk 
storage, lay out your file systems something like this:
/dev/dasd??    /
/dev/vg1/home  /home
/dev/vg1/opt   /opt
/dev/vg1/srv   /srv
/dev/vg1/tmp   /tmp
/dev/vg1/usr   /usr
/dev/vg1/var   /var

And yes, I know that's not the default for all distributions or what everyone 
else thinks should be done, but so be it.

Application space should come from separate DASD volumes or SCSI LUNs, and be 
put in a separate LVM Volume Group, if needing more than one volume or LUN.  
Depending on what you have and who's responsible for it, that could apply to 
the /srv hierarchy as well.  If the space requirements are "modest" (for vary 
values of modesty), and wringing out the last bit of performance isn't 
critical, using DASD is easier to manage today.  If the space requirements are 
large enough, then getting a SCSI LUN assigned makes more sense from a system 
administration perspective than trying to glue a bunch of PVs together.


Mark Post

----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO LINUX-390 or visit
http://www.marist.edu/htbin/wlvindex?LINUX-390

Reply via email to