Mark Post wrote:
On 6/26/2009 at 8:31 AM, "Burton, Randy" <[email protected]> wrote:
[snip....]
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.
I'm seeing that as well, sites new to the mainframe using only SCSI/FCP attached disk storage. While it's not that much more difficult to use, having SCSI/FCP disk means that the disk storage can not be managed by tools like DIRMAINT.
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.
This is true....there is no performance data coming back from the SCSI/FCP disk drives, as that functionality is simply not architectured into the design of those systems. Who was it that said" If you can't measure it, I'm just not interested...."? ;-) These two issues, I believe, are sufficient to support recommendations to new z/VM and mainframe sites that they consider using emulated 3390 (or for that matter, emulated FBA devices) to hold the base Linux install file systems, and leave the SCSI/FCP disk for really big databases/files/etc. [snip....]
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
-- Dave Jones V/Soft www.vsoft-software.com Houston, TX 281.578.7544 ---------------------------------------------------------------------- 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
