Learn how to use a wall clock timer that is included as part of the OpenMP library. Jeff Cogswell walks you through how. Taken from Accurately Time Your Parallel Loops in OpenMP which is found http://goparallel.sourceforge.net/
Month: August 2014
Use GNU C++ and Intel Compilers with OpenMP
Most compilers today support OpenMP. Here is a video compilation of of how Jeff Cogswell shows you how to compile OpenMP programs using both the Intel and GNU C++ compilers. Taken from Use GNU C++ and Intel Compilers with OpenMP from http://goparallel.sourceforge.net
NFS mount errors with “clnt_create: RPC: Unknown host” for CentOS 6
When attempting to mount CentOS 6, my mount fails with
clnt_create: RPC: Unknown host
Diagnostic:
If we do a more thorough diagnostic, this is the issue
# showmount -e clnt_create: RPC: Unknown host # showmount -e localhost Export list for localhost: /export/my_data \*
Resolution:
Taken from Redhat Site
Implement forward and reverse lookups (A records and CNAME records) in DNS and have the system point towards the DNS servers. Implement for both IPv4 and IPv6. If unable to resolve DNS issues, change the /etc/hosts file from this:
Change from
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
To
::1 machine_hostname localhost localhost.localdomain localhost6 localhost6.localdomain6
Restart the NFS service and check on the showmount -e localhost and showmount -e and attempt to mount the share.
# service nfs restart # showmount -e localhost # showmount -e
Assigning ownership to disks for NetApp OnTap 8.2p2 Cluster mode
After replacing broken disks for NetApp Storage and if you want to manually assigned ownership back to the newly replaced but assigned disks, you can use the following command
1. Show Storage Ownership Information
My-NetApp-Cluster::> storage disk show -spare Original Owner: acai-cluster1-01 Checksum Compatibility: block Usable Physical Disk HA Shelf Bay Chan Pool Type RPM Size Size Owner --------------- ------------ ---- ------ ----- ------ -------- -------- -------- cluster1-01:0b.00.9 0b 0 9 B Pool0 BSAS 7200 1.62TB 1.62TB cluster1-01 Original Owner: cluster1-02 Checksum Compatibility: block Usable Physical Disk HA Shelf Bay Chan Pool Type RPM Size Size Owner --------------- ------------ ---- ------ ----- ------ -------- -------- -------- cluster1-02:0a.00.7 0a 0 7 B Pool0 BSAS 7200 1.62TB 1.62TB cluster1-02 ..... .....
2. Display all unowned disks by entering the following command:
My-NetApp-Cluster::> storage disk show -container-type unassigned Usable Container Disk Size Shelf Bay Type Position Aggregate Owner ---------------- ---------- ----- --- ----------- ---------- --------- -------- cluster1-01:0b.00.9 1.62TB 0 9 spare present - cluster1-01 cluster1-02:0a.00.7 1.62TB 0 7 spare present - cluster1-02
3. Assign each disk by entering the following command
My-NetApp-Cluster::> storage disk assign -disk cluster1-01:0b.00.9 -owner cluster1-01
Identify broken disk for NetApp OnTap 8.2p2 Cluster mode
1. Identify the Cluster Nodes
My-NetApp-Cluster::> cluster show Node Health Eligibility --------------------- ------- ------------ cluster1-01 true true cluster1-02 true true cluster1-03 true true cluster1-04 true true 4 entries were displayed.
2. Check for Broken Disk
My-NetApp-Cluster::> run -node cluster1-01 vol status -f RAID Disk Device HA SHELF BAY CHAN Pool Type RPM Used (MB/blks) Phys (MB/blks) --------- ------ ------------- ---- ---- ---- ----- -------------- -------------- failed 0a.00.12 0a 0 12 SA:A - BSAS 7200 1695466/3472315904 1695759/3472914816 failed 0b.00.9 0b 0 9 SA:B - BSAS 7200 1695466/3472315904 1695759/3472914816
3. Get System Information
My-NetApp-Cluster::> run -node cluster1-01 sysconfig -a NetApp Release 8.2P2 Cluster-Mode: Sat Jul 20 20:31:47 PDT 2013 ..... ..... .....
4. Get further Information
My-NetApp-Cluster::> run -node cluster1-01 sysconfig -r Aggregate storage1_aggr1 (online, mixed_raid_type, hybrid) (block checksums) ..... .....
Create export domain or ISO Domain on RHEV 3
This is taken from Red Hat Portal How to create an export domain or iso domain? (Need customer access)
On the NFS, you need to do the following
# mkdir /export/data # chown -R 36:36 /export/data # chmod 755 /export/data # vim /export_data /export/data *(rw) # /etc/init.d/nfs restart # chkconfig nfs on
The key setup is that the ownership must be given vdsm kvm (36:36). Or you will have errors like
“Error while executing action Add Storage Connection: Problem while trying to mount target”
# mkdir /export/ISO # chown -R 36:36 /export/ISO # chmod 755 /export/ISO # vim /export/ISO /export/ISO *(rw) # /etc/init.d/nfs restart # chkconfig nfs on
References:
- Red Hat Enterprise Virtualisation and NFS (NetApp Community)
- How to create an export domain or iso domain? (Red Hat Portal – Restricted Access)
Subscribing to Red Hat Virtualisation Manager Channels
Taken from Red Hat Red Hat Enterprise Visualization Documentation
Step 1: Register the system with Subscription Manager
Run the following command and enter your Red Hat Network user name and password to register the system with the Red Hat Network
subscription-manager register
Step 2: Identify Available Entitlement Pools
Entitlement pools containing the channels required to install the Red Hat Enterprise Virtualization Manager
# subscription-manager list --available | grep -A8 "Red Hat Enterprise Linux Server" # subscription-manager list --available | grep -A8 "Red Hat Enterprise Virtualization"
Step 3: Attach Entitlement Pools to the System
Use the pool identifiers located in the previous step to attach both the Red Hat Enterprise Linux Server and Red Hat Enterprise Virtualization entitlements to the system. Run the following command to attach the entitlements:
# subscription-manager attach --pool=[POOLID]
Step 4: Enable the Required Channels
Run the following commands to enable the channels required to install Red Hat Enterprise Virtualization:
# yum-config-manager --enable rhel-6-server-rpms # yum-config-manager --enable rhel-6-server-supplementary-rpms # yum-config-manager --enable rhel-6-server-rhevm-3.4-rpms # yum-config-manager --enable jb-eap-6-for-rhel-6-server-rpms
The Linux Cluster 