Hi Frank, I started with an installation in 900M. For the installation itself it's good enough but when additional disks were activated I ran into problems. Later I tried in 2G with the same problem. Only when I moved to the target guest (32G) I could successfully enable the application disks. And then I could really see the cause of the problem. When I activated disks the memory usage reported in top was 2.6GB. And I guess, since it's hardware related memory, it is not eligible for swap so the system tries to swap other processes and eventually the oom kills even the critical processes.
Indeed 20 disks might just kept you out of problems but probably you were already close to the edge. Depending on the purpose of the server, we have a lot of small servers. (In the past even as low as 130MB.) We have found that for a Suse zypper update we minimally require about 400MB so that's our baseline for some servers. But even an active Samba machine only has 900M, mostly because of an indexer process that requires quite some memory. Our case for Ubuntu is Machine Learning and this server is currently defined with 32GB, so I could quite easy go into that server to see what was going on after the base installation. Met vriendelijke groet/With kind regards/Mit freundlichen Grüßen, Berry van Sleeuwen Flight Forum 3000 5657 EW Eindhoven -----Original Message----- From: Linux on 390 Port <[email protected]> On Behalf Of Frank Heimes Sent: Tuesday, November 12, 2019 12:22 PM To: [email protected] Subject: Re: Ubuntu 18-04 unable to add DASD Hi, I just completed some rough tests on a pretty small LPAR (just 1.,5GB RAM) and I ran the GA kernel 4.15 as well as the HWE kernel 5.0. An activation of another DASD device requires on kernel 5.0 about 90% less memory compared to kernel 4.15 - so there is indeed a big difference. However, with the 20 DASDs that I had left for the test I wasn't able to run in an OOM situation, but the memory left decreased consistently... Berry, may I ask how big the system is that you are using (regading RAM)? Bye, Frank This e-mail and the documents attached are confidential and intended solely for the addressee; it may also be privileged. If you receive this e-mail in error, please notify the sender immediately and destroy it. As its integrity cannot be secured on the Internet, Atos’ liability cannot be triggered for the message content. Although the sender endeavours to maintain a computer virus-free network, the sender does not warrant that this transmission is virus-free and will not be liable for any damages resulting from any virus transmitted. On all offers and agreements under which Atos Nederland B.V. supplies goods and/or services of whatever nature, the Terms of Delivery from Atos Nederland B.V. exclusively apply. The Terms of Delivery shall be promptly submitted to you on your request. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www2.marist.edu/htbin/wlvindex?LINUX-390
