*** Reply to note of Fri, 10 Sep 2004 12:16:33 -0700 (MST/PDT) *** by [EMAIL PROTECTED]
Using shared disks also helps if you are/want to use linux DCSS support. Then, you have the same problems as a VM's Y-DISK, just much bigger disks and segments ... sal "Wolfe, Gordon W" <[EMAIL PROTECTED]> writes: >This is one possible architecture. Whether it's recommended or not = >depends on why you want to do it. > >The advantages are=20 >1) saving disk space. Depending on how expensive dasd is in your = >organization, this can be considerable. >2) Allowing minidisk cacheing to take place, reducing the number of = >physical I/O's and speeding up response. =20 >3) keeping your users from installing programs or making modifications = >on their own and then calling you at three in the morning when their = >server goes down. then you find out after two hours of work that the = >problem is some modification they made. >4) Creating a "standard" version of Linux that is easily deployable. > >The disadvantages are: >1) Service is much more difficult. You have to install updates on a = >test server, then compare before and after with tripwire to see what = >files were updated on /usr and which were not. You have to route the = >non-/usr files around then swap /usr disks and reboot. You end up = >having almost as many /usr disks with different versions on them than = >you would have if everybody just had their own disk. I've got 38 = >servers and 6 different shared /usr disks, not to mention 4 or 5 servers = >with non-shared /usr. >2) you have altercations with users who want to write to the /usr disk. = >Usually you can get around it by loop-mounting a subdirectory in /home = >over a /usr subdirectory. Installing WebSphere with a read-only /usr is = >virtually impossible, as are other program products. > >I'd say if all of your linux servers are essentially identical, shared = >/usr makes a lot of sense. If they are all configured differently, = >question it. > >We've been using shared /usr for about three years. We are considering = >going to individual read-write /usr areas with SLES9, just for the ease = >in maintenance. Disk is cheap here. We bill our customers only $6.14 = >per gigabyte per month for 3390 dasd storage. A full-pack 3390-3 for = >/usr is about 80% full and is about 2.2GB. > >Check out my presentation at SHARE on this topic at=20 >http://linuxvm.org/present/SHARE101/S9343GWa.pdf > >So one elephant says to another, "You'll never believe what happened = >last night. I was trying on Groucho Marx's pajamas--and he shot me!"=20 >Gordon Wolfe, Ph.D. (425)865-5940 >VM Technical Services, The Boeing Company > >> ---------- >> From: Doug Griswold >> Reply To: Linux on 390 Port >> Sent: Friday, September 10, 2004 11:24 AM >> To: [EMAIL PROTECTED] >> Subject: Shared /usr >>=20 >> I have a question about sharing /usr with multiple vm guests. Is this = >a >> recommended acrchitecture? Are there any benefits to doing this other >> than saving space. It seems to me this could be problematic when >> applying fixes from yast. I welcome any input on this subject. >>=20 >>=20 >>=20 >> Thanks, >> Doug >>=20 >> ---------------------------------------------------------------------- >> 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 >>=20 >>=20 > >---------------------------------------------------------------------- >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
