Depending on what you are putting down, there is no difference, as long as you are using the same device type (3390), as the model doesn't affect overhead factors.
It is the track size (3390 vs 3380) that has the difference in wasted space, concerns. However, if you are using a file system that has a 2 gb limit, specifying anything over a 2 gb drive, would be a waste. The real issue, is when you get into performance... Say, a real raid read, that is reading a raid stripe to get a record, off of disk....say, you can do 100 raid reads a second. If you have a single 3390 volume, you can only do 100 raid reads. If you have two 3390 volumes, defined on different arrays, you can do 200 raid reads a second. etc. So, more, small volumes is better. But, your dasd subsystem, usually has a limit of addresses. If you use all 3390-1 packs, in many subsystems, you can't use all the space you paid for. So, you need larger volumes to use all the space. And, less volumes, is less work for people. (easier to setup 10 volumes than 100 volumes, easier to backup 10 volumes then 100 volumes, disaster recover is easier, etc) And, if you are putting your Linux distribution on a volume and don't plan on filling it up with applications and/or data, you may want to size the volume correctly. So, you end up with a mix of small volumes (for performance, if needed), specifically sized volumes (to hold certain contents), and large volumes (to hold the large stuff, Samba, DB2, Oracle). And, most dasd subsystems can specify other size volumes, say 2000 cylinders, or 400 cylinders. Those weird size volumes can be used to fill out the rest of the array, as there is always some space left over after you carve up the array. For me, with an IBM DS6800, I started defining 3390-3 devices. And then as I grew my Linux stuff, I saw reasons to have 3390-9 and 3390-27 devices, and also some 3390-1. But then, I have dozens of Linux images. Tom Duerbusch THD Consulting >>> "Lionel B. Dyck" <[EMAIL PROTECTED]> 5/9/2007 11:41 AM >>> We are trying to decide which 3390 model to configure in our incoming storage device (probably emc but could be shark). The point of interest is which model provides the least amount of 'wasted' space due to overhead requirements. Here is a chart that I've cobled together from a few web sites and you'll notice that the usable bytes column is empty. Disk Type Data cylinders Tracks per cylinder Bytes per track Bytes per cylinder Bytes per module GB per module Spare Cylinders Usable Bytes 3390-1 1113 15 56,664 849,960 946,005,480 0.95 1 3390-2 2226 15 56,664 849,960 1,892,010,960 1.89 1 3390-3 3339 15 56,664 849,960 2,838,016,440 2.84 1 3390-9 10017 15 56,664 849,960 8,514,049,320 8.51 3 3390-27 32760 15 56,664 849,960 27,844,689,600 27.84 3 3390-54 65520 15 56,664 982,800 55,689,379,200 55.69 3 Thanks Lionel B. Dyck, Consultant/Specialist Enterprise Platform Services, Mainframe Engineering KP-IT Enterprise Engineering, Client and Platform Engineering Services (CAPES) 925-926-5332 (8-473-5332) | E-Mail: [EMAIL PROTECTED] AIM: lbdyck | Yahoo IM: lbdyck Kaiser Service Credo: "Our cause is health. Our passion is service. We?re here to make lives better.? ?Never attribute to malice what can be caused by miscommunication.? NOTICE TO RECIPIENT: If you are not the intended recipient of this e-mail, you are prohibited from sharing, copying, or otherwise using or disclosing its contents. If you have received this e-mail in error, please notify the sender immediately by reply e-mail and permanently delete this e-mail and any attachments without reading, forwarding or saving them. Thank you. ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
