Dienstag, 28. November 2017

Lustre 2.10.x dkms usage

get the src for the lustre-client-dkms package from the:

1) rpmbuild --rebuild --without servers lustre-client-dkms-2.10.2_RC1-1.el7.src.rpm
2) yum install /root/pmbuild/RPMS/noarch/lustre-client-dkms-2.10.2_RC1-1.el7.centos.noarch.rpm
It will rebuild the modules for the active kernel with the following commands:
/bin/bash /sbin/dkms build -m lustre-client -v 2.10.2_RC1 -k 3.10.0-693.5.2.el7.x86_64

PS troubleshooting
if dkms  status shows something like this:
 dkms status
lustre-client, 2.10.2_RC1, 3.10.0-693.5.2.el7.x86_64, x86_64: installed (original_module exists) (WARNING! Diff between built and installed module!) (WARNING! Diff between built and installed module!) (WARNING! Diff between built and installed module!) (WARNING! Diff between built and installed module!)
1) dkms --force remove  -m  lustre-client -v 2.10.2_RC1 -k 3.10.0-693.5.2.el7.x86_64
2) rm -fr  /lib/modules/3.10.0-693.5.2.el7.x86_64/extra/lustre
3) find and remove manually the module leftovers: find /lib/modules/| grep lustre
4) dkms --force install -m  lustre-client -v 2.10.2_RC1 -k 3.10.0-693.5.2.el7.x86_64

Mittwoch, 15. November 2017

Deleting the funny 192.168.122.xxx network from CentOS 7.4

In order to stop unnecessary interface on the VM:
yum install -y libvirt-client
systemctl start  libvirtd 
virsh net-destroy default
systemctl stop  libvirtd 
systemctl disable  libvirtd 


Dienstag, 17. Oktober 2017

Performance consumer nvme ssd vs samsung evo pro SSD

Micron 1100 256GB M.2 vs Samsung SSD 850 EVO 1TB

Micron vs Samsung

List used ciphers on remote HTTPS server

Nmap is your friend:
nmap -sV --script ssl-enum-ciphers -p 443 remote.server.my

Dienstag, 12. September 2017

Again lustre upgrade troubles: unable to mount after upgrade to 2.10.x

The failure is following:
LDISKFS-fs (sda): Unrecognized mount option "context="unconfined_u:object_r:user_tmp_t:s0"" or missing value
But Selinux is disabled so we should remove that mount options.
To fix it:
tunefs.lustre --mountfsoptions="user_xattr,errors=remount-ro" /dev/sda
mount a expected.

Recover a single file on the Lustre due to the OST corruption.

Assuming the OST number 4 is corrupted.to get the ost ID on the client one can use lfs df  :
lfs df /archive
UUID                   1K-blocks        Used   Available Use% Mounted on
arch-MDT0000_UUID       99428812    44432680    48286884  48% /archive[MDT:0]
arch-OST0000_UUID    63838042896 46275072544 14344891120  76% /archive[OST:0]
arch-OST0001_UUID    63838042896 46036859640 14583104024  76% /archive[OST:1]
arch-OST0002_UUID    63838042896 34406650692 26213311960  57% /archive[OST:2]
arch-OST0003_UUID    63838042896 39355270936 21264676344  65% /archive[OST:3]
arch-OST0004_UUID    63838042896  7102256308 53517690972  12% /archive[OST:4]
If the OST got corrupted then file attributes are still on MDS so we can filter all corrupted files by following:

lfs find /archive --ost 4  -type f | xargs -I% sh -c "[ ! -f % ]&& echo %" | tee -a recover/todo/OST04-corrupted.txt
this is assuming that files does not contain spaces or nasty characters. For the general case one should use python script for the proper handling of the filenames.

Now once the file list is complete, one can use following script to copy the files over the corrupted files, here we assume that the backup path is /backup and target path is /archive:

 cat recover.sh
cat $file   | xargs -I{} sh -c  "[ -f \"/backup{}\" ]&&echo 'unlink \"{}\";cp -a \"/backup{}\" \"{}\"' "| parallel  --progress --eta 

./recover.sh recover/todo/OST04-corrupted.txt

Freitag, 8. September 2017

Running ANSYS on LINUX

Check which version is installed:
ls /ansys_inc/

If you want to run v182 then the simple answer is: