Re: CMS-like 'xmitmsg' for Linux (or Unix or MacOS or maybe even Windoze)

On Fri, 17 Mar 2023 at 14:45, Neale Ferguson wrote: > I believe in the early 2000s the Linux on 390 developers in Böblingen > attempted to provide a similar mechanism for the kernel but it wasn't well > received by the rest of the community. It's a pity but with so many hands > involved with so

Re: trying to recover existing install

On Sun, 30 Jan 2022 at 12:10, Neale Ferguson wrote: > If there's no password at all on those disks then you'll need their z/VM > sysprogs to either (a) add the word 'ALL' to the MDISK statement of the > failing guest or (b) add LINK RR statements to the > recovery user's directory

Re: X Windows System setup on Ubuntu Server 18.04.

On Fri, 28 Jan 2022 at 13:01, Steffen Maier wrote: > > > If that doesn't work, I'll try Xvnc instead of Xorg. > > I think that's the only way if you want an X server in Linux on IBM Z. > But the more common approach is to ssh -X into your Linux on IBM Z server and allow your ssh configuration

Re: Elasticsearch and Openshift on zVM - Suffering from CPU steal ?

On Sat, 6 Feb 2021 at 12:45, Mariusz Walczak > > So far everyone is just saying "you need more IFLs". But why do I need more > IFLs if I'm using 40% of CEC IFL capacity ? Anyone interested in z/VM performance would indeed want to study monitor data from the two situations. I’m no smarter to try

Re: CP overhead of using FCP attached SCSI SAN

On Thu, 5 Nov 2020 at 16:23, Dave Jones wrote: > So handling this approximately 1K times could drive the %steal up, I > think. > That appears to be nmon failing, probably picking up a stale pointer or following some bunny trail. It's something to pick up with Nigel. It does not directly

Re: CP overhead of using FCP attached SCSI SAN

On Wed, 4 Nov 2020 at 20:06, Rob van der Heij wrote: > > On Wed, 4 Nov 2020 at 19:30, Dave Jones wrote > > What is the CP overhead of managing this? The one Linux guest that is >> running here reports a %steal of 15-17%, which I think is a bit high. >> > At

Re: CP overhead of using FCP attached SCSI SAN

On Wed, 4 Nov 2020 at 19:30, Dave Jones wrote What is the CP overhead of managing this? The one Linux guest that is > running here reports a %steal of 15-17%, which I think is a bit high. > Could this be configured better? > Thanks, appreciate it. You’re right that EDEV overhead would show in

Re: performance problems db2 after moving from AIX

On Tue, 3 Nov 2020 at 21:27, Grzegorz Powiedziuk wrote: > > In the performance monitor toolkit it shows around 12.000 diag x'9c' /s > and 50 x'44' > But at this time of a day everything is calm. i will check again tomorrow. > Lot's of diag x'9c' would indicate too many virtual cpus right? > You

Re: Running multiple Oracle on a single Linux guest

On Wed, 17 Jun 2020 at 09:14, Peter wrote: > So I can't cap memory based on a oracle instance ? Like prioritising each > oracle instance ? > You can to some extent. You define the maximum by SGA and PGA per instance, and things like connection pools. The actual usage varies somewhat by

Re: Running multiple Oracle on a single Linux guest

On Wed, 17 Jun 2020 at 07:06, Peter wrote: We have 2 IFLs for zVM(non SSI). We are planning to run multiple instances > of oracle on a single Linux guest server. > > Almost these oracle are expected to have a very low workload. > > Is anyone in the group who are running a similar workload and is

Re: Docker image query

On Tue, 16 Jun 2020 at 08:59, Peter wrote: > > When we pull a docker image of oracle on zlinux. How does this allocate on > the given LUNS or storage ? Can I customise a existing docker image ? > I don't know whether there are docker images for Oracle on IBM Z, but in general you mount the

Re: [EXTERNAL] Re: z15 on-board compression

On Wed, 10 Jun 2020 at 15:28, Rob van der Heij wrote: > On Wed, 10 Jun 2020 at 14:55, Peter Webb, Toronto Transit Commission < > peter.w...@ttc.ca> wrote: > >> Hi Rob, >> >> Could you please point me to a list of the cipher suites with CPACF >> suppo

Re: [EXTERNAL] Re: z15 on-board compression

On Wed, 10 Jun 2020 at 14:55, Peter Webb, Toronto Transit Commission < peter.w...@ttc.ca> wrote: > Hi Rob, > > Could you please point me to a list of the cipher suites with CPACF > support? > If you're current on openssl in Linux, just stick with the AES ciphers like aes256-ctr. Since the later

Re: z15 on-board compression

On Wed, 10 Jun 2020 at 14:24, Michael MacIsaac wrote: So the compress is about 32% faster on the z15 and the decompress is about > 76% faster. I'm not trying to get the best numbers possible, rather, I'm > trying > to see what gains we might expect to see in the real world. Again, this > may

Re: z15 on-board compression

On Wed, 10 Jun 2020 at 07:06, Neale Ferguson wrote: > Also, take a look at my post from last week. I used /dev/urandom as the > "real" test case and /dev/zero as "best case". > Ah, but random numbers are not cheap either. I use two large files on the CMS S-disk as my input and repeat them with

Re: SFTP vulnerability

On Tue, 14 Apr 2020 at 13:48, Alan Altmark wrote: > Further, there’s no > equivalent of “certificate validation.” > Well, there’s the knownhosts file, but more tempting to ignore and override than what browsers do now. You can however train the configuration to use an LDAP registry to hold both

Re: Public key for sftp

It goes in the .ssh/authorized_keys file for that user. Be aware that ssh is picky about permissions On Mon, 13 Apr 2020 at 11:37, Peter wrote: > Hello Group, > > I have created SFTP server on linux . User has given us public key . > > Where exactly the public key have to be placed in linux so

Re: Nostalgia

On Fri, 14 Feb 2020 at 23:50, Neale Ferguson wrote: > For those who remember BITNET, RELAY, and VMSHARE. Here’s a video showing > its resurrection. > > https://youtu.be/gsY_m8ufcs4 I recognize that web page at the start :-) Sir Rob the Plumber

Re: Happy birthday

On Fri, 20 Dec 2019 at 02:49, Neale Ferguson wrote: > Here are some birthday-inspired nostalgia: > And we were cross-compiling things like glibc, which means using the compiler and tool chain on x86 to build the executable code for s390. You tell the tools to put those s390 executable parts in

Re: Happy birthday

On Thu, 19 Dec 2019 at 03:34, Rich Smrcina wrote: > I’m sure there were more than a few of us installing the ‘Marist’ > distribution on our mainframes over Christmas. > For me the journey started a bit earlier, working on Melinda's system in Princeton. I told my wife this was significant for

Re: Why Linux Developers Should Reconsider IBM Mainframes - Linux.com

On Mon, 14 Oct 2019 at 14:05, James Tison wrote: > Now that I think about it, I don't think there was ever an i390 -- although > there was an i370, which died a long time ago (based on the very first port > True, I was thinking of i370. My apologies. I still remember when I made a typo when

Re: Why Linux Developers Should Reconsider IBM Mainframes - Linux.com

But it’s true that those terms are not used outside Linux on System Z. Even though zArchitecture isn’t an appealing name. And we don’t hear much about i390 anymore  On Sun, 13 Oct 2019 at 15:41, Neale Ferguson wrote: > Yes and still is. If you execute the ubame command it will shows s390x. >

Re: Redhat build first time

On Mon, 2 Sep 2019 at 06:30, Jake Anderson wrote: Any clue how can I turn LNXADMIN into R/W ? > LINK W ACCESS A FTP ... -- For LINUX-390 subscribe / signoff / archive access instructions, send email to

Re: SLES 15 - no help?

eah, maybe z/VM should deprecate XEDIT and HELP in v8 and have people use > something more modern (hehe). > > -Mike > > On Sun, Jun 9, 2019 at 7:56 AM Rob van der Heij wrote: > > > We could argue that a server can do without, and I’ve always complained > the > >

Re: SLES 15 - no help?

We could argue that a server can do without, and I’ve always complained the minimal was too much. The container stuff likely focus them. It may be too minimal for manual sysadmin work. I think it lacks sudo as well. And I hate they put ifconfig cs in nettools-very-much-deprecated in some other

Re: RHEL Install in a LPAR

On Thu, 21 Mar 2019 at 16:04, Huckert, James A < james_a_huck...@homedepot.com> wrote: > > Does anyone know a way to install RHEL on a EC13 without using the HMC? > I thought there was a way to format a volume from z/OS 2.3 and lay down > the needed files and boot RedHat. > > Due to security

Re: zLinux in the news

On Sun, 6 Jan 2019 at 22:59, Alan Altmark wrote: > > I think it's (totally) awesome that when I file my 2019 taxes in 2020, > parts of the e-file application will be running on Linux on Z! Caveat: It > has been noted in the media that the current partial US government > shutdown affects the

Re: question on SWAPGEN preferences

I don’t see how specifying the size should make a difference, apart from the last odd blocks when an arbitrary size does not make a full number of cylinders. If you’re talking VDISK then it seems irrelevant since there’s just a doze blocks to be written at any size. With 3390 we can’t really

Re: single user mode under z/VM

On 16 May 2018 at 20:23, Terri C. Glowaniak wrote: > Just wondering what 'console' people use to access their Linux systems > when using 'single user mode' ... 3270, IUCV, or ? > > Back when I was involved, we used logging through secondary console to see what

Re: [EXTERNAL] Re: zLinux tools and toys site for Developers

On 15 May 2018 at 19:31, Chu, Raymond wrote: We do use it extensively on our development environment to clean things up > after the evening compliance scanning and backups that are memory > intensive. It runs at a random minute in the 4am hour to avoid running it > on all

Re: zLinux tools and toys site for Developers

show me > > the url. > > I am not aware of anything called Tools and Toys related to Linux on IBM > Z. The cmmflush script was created by Rob van der Heij, and published on > his blog https://zvmperf.wordpress.com . If you're having a problem with > cmmflush, Rob may (or may

Re: Remote exec script

On 26 January 2018 at 05:25, Rogério Soares wrote: > Exactly Mauro... I want a way to run some execs on another ssi member... > Whithout need logon.. ssicmd just execute cp commands... > If you have a Linux guest on one of the members, you can issue some CP commands

Re: Auto login root on 3270 console ttyS0

On 16 August 2017 at 00:47, Rick Troth wrote: > > It's arguable that having to enter a password at a "login:" prompt would > actually be /less/ secure. > Indeed. It can be argued, and I did that a lot :-) A lot of the security rituals we follow were created for problems that

Re: High steal on z/linux guest

On 21 April 2017 at 22:10, Alan Altmark wrote: > > I googled "z linux steal time" and got a lot of hits. But, again, it's > not a z-only phenomenon. > LOL Look what I googled :-) http://www.rvdheij.nl/Presentations/cpusteal.pdf "Concern about latency without looking

Re: Redmine on zLinux?

ks like it also needs Ruby on Rails. Does that run on > zLinux? > > Thanks. > > -Mike > > On Fri, Mar 10, 2017 at 2:18 AM, Rob van der Heij <rvdh...@gmail.com> > wrote: > > > You probably need zlib-devel or whatever package your distribution is > &g

Re: Redmine on zLinux?

You probably need zlib-devel or whatever package your distribution is shipping that in. The library is most certainly available for s390x. On 9 March 2017 at 21:52, Michael MacIsaac wrote: > Hello list, > > Has anyone tried to install redmine on zLinux ( see >

Re: WWN change

And it almost feels like cheating to use ECKD devices on FICON where you only configure in one place  On Oct 30, 2016 11:56 AM, "Christer Solskogen" wrote: > On Fri, Oct 28, 2016 at 1:24 PM, Steffen Maier > wrote: > < a lot> > > This was

Re: Logs from Operator

You could run PROP and pass all to syslogd on Linux. On Aug 13, 2016 7:31 PM, "joão paulo limberger (shoo)" wrote: > Hi All! > > I want to receive in a linux VM all the messages sends to the console of > the user Operator ... > > What is the best way to do this? > >

Re: Back to the future?

On 27 July 2016 at 14:09, Martin Schwidefsky wrote: > Are you referring to the RTC clock interface of the kernel? If so then yes, > that never worked for s390. If you look into drivers/rtc/Kconfig you'll > find this: > > No, I meant the HWCLOCK setting in the startup

Re: Back to the future?

On 26 July 2016 at 19:33, Marcy Cortes wrote: > Martin wrote: > > >Either the sysadmin or NTP should do this, otherwise the system clock > will be off by 26 seconds (soon 27 seconds as another leap second is > scheduled). > > This kind of implies that if I disable

Re: x-11 on SLES

Since we don't have a bit - mapped graphics display to use, there are two options 1. Run VNC server on the z side to emulate the display, use a VNC viewer or web-based java viewer to see it 2. Run x 11 display on your workstation and have x11-forwarding enabled which sets the DISPLAY variable.

Re: VM EDEVICE multipath for Linux

On 28 April 2015 at 16:38, Sergey Korzhevsky s_korzhev...@iba.by wrote: Any idea why The Virtualization Cookbook for IBM z/VM 6.3, RHEL 6.4, and SLES 11 SP3 (latest, i think) does not mention this setup? Maybe there some hidden problems? One of the challenges is performance, since there's

Re: Java performance under a second level VM

Things may be more clear when you see ttime for the guest on 1st level. I suspect you see the missing cycles there. It's not 2nd level CP doing the hard work but 1st level. Rob -- For LINUX-390 subscribe / signoff / archive

Re: Java performance under a second level VM

The JIT for example uses polling to sample the state. It sets a timer to pop in a few ms and goes to sleep. But since that state change and timer interrupt reflection isn't in hardware the cost appears excessive. If you would be computing pi second level in Linux it may still be pretty decent. And

Re: Java performance under a second level VM

On Apr 17, 2015 9:40 AM, Pavelka, Tomas tomas.pave...@ca.com wrote: This is probably too specialist topic for general consumption. I find this pretty fascinating, not sure about the others. If no one else replies let's move this offline. Yes me too. But i have that with most exotic

Re: Java performance under a second level VM

Yes. Hardware virtualization support (aka SIE) is only two levels: LPAR and z/VM. Linux running its processes is one too many so must be done in software. That creates overhead. In your case is likely the polling of the JVM that does it, which means is not really related to workload but just

Re: How do I assign a read password to a disk

Minidisk passwords are in the directory and can be set when you issue the amdisk or afterwards. If you have racf you use that. But you may want to rethink that approach from a security point of view. Are you talking about CMS or Linux? Have you considered NFS or SFS where people can publish what

Re: Network Time Protocol Daemon needed for zLinux?

Just a warning: my understanding is that this quote is talking about Linux in LPAR; that z/VM does not virtualize the ETR/STP. For the rest of us: When you have STP steer the LPAR TOD to keep z/VM on time, Linux will inherit the same (UTC) TOD and runs better on time than anything you can do with

Re: Network Time Protocol Daemon needed for zLinux?

On 18 March 2015 at 21:00, Vitale, Joseph joseph.vit...@bnymellon.com wrote: Using STP to set clock for zVM LPAR. zVM and zLinux guest show time, both in sync. Trying to avoid setting up NTPD and starting on all zLinux if not necessary. Sorry to complicate it, but that check is not

Re: Network Time Protocol Daemon needed for zLinux?

On 18 March 2015 at 23:02, Scott Rohling scott.rohl...@gmail.com wrote: Not sure how strongly you were asked :) -- but I would explain that z/VM-Linux are already synced with whatever NTP server the z is using.. and I would ask why it should then be necessary. Put the burden of

Re: Network Time Protocol Daemon needed for zLinux?

On 18 March 2015 at 20:04, Vitale, Joseph joseph.vit...@bnymellon.com wrote: My Linux runs under zVM, not in a stand alone LPAR. So, NTP or STP not required, correct ? That depends on whether you have STP steer the clock for the LPARs. It's a priced feature. If Q TIME on z/VM is now very

Re: IP Sprayer

infrastructure by virtualizing it, not complicate it. Rob van der Heij http://www.velocitysoftware.com/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX

Re: IP Sprayer

application, and monitor usage for those values and add resources when needed. Rob van der Heij http://www.velocitysoftware.com/ On 13 March 2015 at 08:52, Berthold Gunreben b...@suse.de wrote: Hi, Starting with SLES12, there is haproxy included in the HA part of SLES. http

Re: Dasd question

Can you see it with lsdasd -a maybe? If so, then chccwdev -e might bring it online? If that works, it sounds like you're missing the udev rules that specify which devices to use. An easy way out is to use yast to activate the device and have that build the rules and generate the initrd for you

Re: SUSE dump file location

You need to escape the wildcards to avoid bash glob it. find -name \*.log On Mar 10, 2015 7:06 PM, Duerbusch, Tom duerbus...@stlouis-mo.gov wrote: I was looking to reclaim some disk space. find / -name *.log showed some likely candidates. Now looking for obsolete dumps. find / -name

Re: Crypto Express Measurements

workloads. -Rob On Mar 6, 2015 11:46 AM, Rob van der Heij rvdh...@velocitysoftware.com wrote: On 6 March 2015 at 17:23, Rob D robster3...@gmail.com wrote: Rob what workload are you looking to compare? SSL would make use of the CPACF facility in the Z procs themselves. Crypto cards

Re: Crypto Express Measurements

On 6 March 2015 at 17:23, Rob D robster3...@gmail.com wrote: Rob what workload are you looking to compare? SSL would make use of the CPACF facility in the Z procs themselves. Crypto cards assist in key exchange and Z\OS type workloads. Zlinux workloads tend to use libs that don't use crypto

Re: Oracle 11G Installation on SUSE 11 for Z

On 6 March 2015 at 09:48, SrinivasG sriniv...@infosys.com wrote: Hi , While installing Oracle 11G on SLES 11 on Z10BC IFL , Oracle Installation was asking for 4GB RAM. So I increased from 2GB to 4.5 GB RAM in HMC and performed IPL. Increased Swap Space to 12GB. Yet when I restarted Oracle

Crypto Express Measurements

installed and would like to use it (or want to verify that it's being used) then I would be happy to try answer your questions and understand what performance questions need to be answered. Rob van der Heij http://www.velocitysoftware.com

Re: Docker on z

On 6 March 2015 at 22:08, Utz Bacher utz.bac...@de.ibm.com wrote: Hi Mark, Mark Post mp...@suse.com wrote on 06.03.2015 20:10:15: Hmm. I thought IBM employees were not allowed to distributed binaries of open source software outside of the company. Has this changed for the better?

Re: vmstat just plain wrong?

in the code. You know I'd be more happy to look at the data and see what can be explained from it. Rob van der Heij http://www.velocitysoftware.com/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email

Re: Optimum Hipersocket MTU

On 28 January 2015 at 15:03, Donald J. dona...@4email.net wrote: Not sure about massive, but fairly large, 16.5M rows. The initial build and index setup took 8.1G diskspace on Linux. I will get a packet trace. That sounds like enough to at least consider to worry about things. The benefit

Re: Optimum Hipersocket MTU

On 28 January 2015 at 14:20, Donald J. dona...@4email.net wrote: Can anyone recommend the best hipersocket MTU size for DB/2 Text Search from z/OS to z/Linux ? Choices are 8k/16k/32k/56k. In many cases it probably will not matter unless the data volume is really massive. If it does matter,

Re: SLES12 / partitioning

On 18 December 2014 at 20:26, Mark Post mp...@suse.com wrote: On 12/18/2014 at 09:32 AM, Levy, Alan al...@doitt.nyc.gov wrote: Does it make sense in just setting up one mod 29 (32000+ cylinders, app 21G) and let the btrfs use the whole thing instead of breaking it up into smaller pieces

Re: hyperpav setup

distributions). Rob van der Heij http://www.velocitysoftware.com/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http

Re: hyperpav setup

On 5 November 2014 21:04, Alan Altmark alan_altm...@us.ibm.com wrote: On Wednesday, 11/05/2014 at 02:48 EST, Rob van der Heij rvdh...@velocity-software.com wrote: Isn't that what you define HYPERPAVALIAS for? Yes, but it only works with fullpack minidisks. See Usage Note 3 on DEFINE

Re: dasdfmt problem when building a new Red Hat guest

On 3 November 2014 23:39, Alan Altmark alan_altm...@us.ibm.com wrote: I see installations that run ICKDSF CPVOLUME FORMAT (CPFMTXA) or ICKDSF INIT against he whole volume, then turn around and give it to Linux to run dasdfmt. (I think there's still some sort of residual institutional

Re: Installing Java security policy files on IBM JDK

...@autodata.no wrote: Thanks, Rob. You never let me down. Looking at this documentation for Java security, I feel like the kid in the barn yard - digging through the muck. With all this manure, there's gotta be a pony somewhere. Roger On Fri, 2014-10-24 at 15:57 +0200, Rob van der Heij wrote

Re: Installing Java security policy files on IBM JDK

The unrestricted policy files (ie not limited to short keys) are at http://www.ibm.com/developerworks/java/jdk/security/index.html and instructions are here: http://pic.dhe.ibm.com/infocenter/lmt/v7r2m2/topic/com.ibm.license.mgmt.security.doc/lmt_scr_downloading_installing_jce_policyfiles.html On

Re: Floating Point libraries on Z-Linux

Hej Roger, Did you also install libdfp-devel from the SDK disk? It appars to ship for header files for /usr/include/dfp Rob On 9 October 2014 08:48, roger ro...@autodata.no wrote: Does anybody have any experience using decimal floating point libraries from C/C++ on Z-Linux? I have

Re: Disabled wait state 1124EC when IPL'ng SLES 11 on z/vm 5.3 eval

On 5 October 2014 23:02, mstram . mikestra...@gmail.com wrote: it goes into disabled wait state 1124EC. Is that wait state related to CP msg 1124 ? No, entirely unrelated. It's just the address in the kernel where the disabled wait was loaded. In this case probably in the on_panic_notify()

Re: How to reset the Linux root pw

On 3 October 2014 08:07, Cameron Seay cws...@gmail.com wrote: Hi: I know how to reset the root password on an x86 machine using single user mode. Is there a way to do that in Linux on VM? You can shutdown the guest and boot in single user mode by specifying the 1 on the kernel parameters:

Re: How to reset the Linux root pw

On 3 October 2014 08:33, Pavelka, Tomas tomas.pave...@ca.com wrote: warm bodies authenticate with PKI using a central LDAP store for public keys Being curious, how do you deal with situations when LDAP is temporarily not available? Would you want users to access your system when you can't

Re: How to reset the Linux root pw

On 3 October 2014 15:37, Alan Altmark alan_altm...@us.ibm.com wrote: And if all else fails, the procedures Rob described are at your disposal if you need to repair something (e.g. a bad LDAP configuration). And since someone mailed me about IPL of a rescue system - only if that makes you come

Re: zLinux Perf problem with OpenCobol and C and libgmp under RHEL65

are other than what has been discussed on the thread, but would need more numbers to avoid guessing. I would be most happy to dig into this with you offline and explain what we can do for you in this area. Rob van der Heij http://velocitysoftware.com

Re: ECKD DASD Sizes

. In the right configuration, Parallel Access Volumes (PAV) could address some of those challenges if that is licensed with the new DASD. You're most welcome to send me some of your data to discuss your migration plans. Rob van der Heij http://velocitysoftware.com

Re: file corruption on RHEL 5.8

On Wed, Oct 2, 2013 at 7:17 PM, Donald Russell russell@gmail.comwrote: In the case I'm currently working on, a .so file (binary) has a chunk of plain text in the middle of it. The chunk is 4K bytes long, and is a piece of a program listing. 4K is the block size of the underlying DASD. I

Re: z/VM 6.3 upgrade installation ESM considerations

On 21 August 2013 20:31, Alan Altmark alan_altm...@us.ibm.com wrote: From an ESM perspective, realize that changing the indirect LINKs in MAINT to point to MAINT630 *may* drive a lot of permission changes. E.g. People who LINK MAINT 490 today have authorization to MAINT620 490. Now they

Re: z/VM 6.3 upgrade installation ESM considerations

On 22 August 2013 14:45, Alan Altmark alan_altm...@us.ibm.com wrote: All good suggestions must be submitted 3 times to assure their veracity and continued relevance. This is only twice. ;-) It's impressive how brave you get once outside reach of any flying heavy office furniture (lol)

Re: linux cache

of $100. Mauro http://mauro.limeiratem.com - registered Linux User: 294521 Scripture is both history, and a love letter from God. 2013/8/15 Rob van der Heij rvdh...@gmail.com On 15 August 2013 17:34, Mauro Souza thoriu...@gmail.com wrote: You can safely ignore the cache usage

Re: linux cache

- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Rob van der Heij Sent: Friday, August 16, 2013 5:22 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: linux cache The thing that happened to your servers is that drop_caches frees up page frames in Linux that have not been

Re: linux cache

On 16 August 2013 16:13, Veencamp, Jonathon D. jdveenc...@fedins.comwrote: I appreciate the creative thought. Keeping the JVM active for INACTIVE development servers is kinda going in the wrong direction. What I really need is a kernel modification where I could cap the linux file cache

Re: linux cache

On 15 August 2013 16:44, Dean, David (I/S) david_d...@bcbst.com wrote: Is there any benefit (or negative) to running a drop_cache periodically? I don't find it helpful in most cases, especially since it does not reduce the server footprint. Shaking up memory like that may even make performance

Re: linux cache

On 15 August 2013 17:34, Mauro Souza thoriu...@gmail.com wrote: You can safely ignore the cache usage on Linux, zVM will realise the page was not in use and drop it itself. When Linux needs memory, it will reclaim cache pages automatically. So we disagree. Maybe we wouldn't if you had read

Re: TX-Errs on hipersocket interface.

On 2 August 2013 13:45, Billy R. Bingham brbing...@stx.rr.com wrote: I for one would like to know. :) You don't have to post to the list, you can email me private, or if you perfer you can post a URL where I can read about it. Right! Did someone miss the fact that it's Friday? First thing

Re: Adding space to Logical Volume Group by expanding the underlying physical disks?

On 21 June 2013 17:34, Eric Chevalier et...@tulsagrammer.com wrote: Greetings! We run a TSM server on a virtual RHEL6 system hosted by z/VM. The TSM databases are stored on a logical volume group that's getting close to running out of space. An obvious solution would be to add more DASD to

Re: Appropriate hipersocket MFS size for use with SAP Apps Servers

On 15 June 2013 17:58, Ron Foster ron.fos...@baldor.abb.com wrote: Rob, The traffic is between our Sap application servers running under zvm. I'm surprised the traffic would be that impressive. Normally I see bandwidth requirements with SAP for the transport data via NFS. For the real

Re: Appropriate hipersocket MFS size for use with SAP Apps Servers

On 13 June 2013 23:58, Ron Foster ron.fos...@baldor.abb.com wrote: 3. One of the things that the TCP IP folks want us to do on the hardware side is to increase the maximum frame size to 64k. for this hipersocket. 4. This would normally increase the MTU size to 56k for the hipersocket. 5. If

Re: Amount of memory in buffers shown by the free command

On 17 May 2013 01:55, Suthammanont, Alex C alex.suthamman...@bankofamerica.com wrote: Mike Rob, That is not what I see at my end. Below are sample of RHEL 5.9 and RHEL 6.3. In both cases, the number of cached from the 'free' command matches to the number of cached found in /proc/meminfo.

Re: Amount of memory in buffers shown by the free command

It's Friday, but I still don't feel like installing all the dependencies to build the procps package... I believe the smoking gun is on my desk already: procps-3.2.7-slab.patch (part of the SUSE add-ons to procps) says @@ -603,6 +615,7 @@ } kb_swap_used = kb_swap_total - kb_swap_free;

Re: Amount of memory in buffers shown by the free command

On 15 May 2013 17:00, Michael MacIsaac mike...@us.ibm.com wrote: Does anyone know why free shows a different amount of cached memory that /proc/meminfo? For example: It's documented that Cached: in /proc/meminfo does not include swap cache, while the value from free does. But there's still

Re: Big Dumps

I believe it is normal procedure to create a menu entry with zipl to do a stand-alone dump of the guest. For large guests you may need to prepare for multi-volume dump. If you're brave you could set up a single set of minidisks and link them when you need to dump. With FCP you may be able to use a

Re: Oracle replication from linux x86_64 to linux on z

On 2 May 2013 16:04, John Campbell soup...@gmail.com wrote: Unless the DataBase engine makes an effort to handle all non-internal-code numbers in an interchangable format-- and with appropriately fixed sizes-- the binary form of the data file-- or container files, for a database-- will be

Re: Putty security

On 6 March 2013 21:31, Peter Webb, Toronto Transit Commission peter.w...@ttc.ca wrote: As a replacement, check out BlueZone VT from Rocket Software http://www.rocketsoftware.com/. You sure? At least they only mention TN3270 over SSL etc. For SSH the easiest is probably a Linux desktop, and

Re: Problem with iucvconn under SLES 11 SP2

On 4 March 2013 11:17, Florian Bilek florian.bi...@gmail.com wrote: Dear Hendrik, This is the new configuration provided by SP2: agetty started by /sbin/ttyrun. However I tried it already also with mingetty as it had it before. h0:2345:respawn:/sbin/ttyrun hvc0 /sbin/agetty -L 9600 %t

Re: Speed of BASH script vs. Python vs. Perl vs. compiled

On 31 January 2013 22:01, Philipp Kern pk...@debian.org wrote: even quite old Intel boxes manage to saturate 1 GE easily. You're copying stuff into the send buffer and ring a bell. Nowadays it doesn't seem hard to do 10 GE with a Linux box, especially if you've got HW assist on the network

Re: Speed of BASH script vs. Python vs. Perl vs. compiled

might be able to help tune the buffers (which is harder than just making them bigger). Rob van der Heij Velocity Software http://www.velocitysoftware.com/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email

Re: Speed of BASH script vs. Python vs. Perl vs. compiled

On 30 January 2013 05:17, Patrick Spinler spinler.patr...@mayo.edu wrote: Since no one else seems to be pointing this out, i can see at least one potential optimization: This will re-open the output file and seek to the end every output. That's a factor of 2 or 3 more syscalls every time.

Re: Twin penguins prospered for 417 days, then died

On 14 January 2013 16:37, Juha Vuori juha.vu...@pp2.inet.fi wrote: If you can optimize the code even so that the next overflow happens only after 143 years, I have to send a note to my becoming grand-grand-children so that they will remember to take zlnx011 down in _controlled_ way just

Linux EAV and DFSMSDSS

Anyone doing his Linux backups (and restore) with DFSMSDSS maybe? A friend wanted to start using EAV and defined some 170G disks, through DEVNO managed on z/VM. And while it seems the backup may have worked, the restore certainly doesn't and complains with ADR024E and some strange cylinder

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