| Question |
| Basic function of load balancer ? In which setup it is most useful ? |
| Answer |
| DM load balancer is setup your devices with multiple paths in a structured way through which you can prevent your path failover automatically and load control I/O transaction in unix Host. |
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| Question |
| Whether we should prefer Hardware Load Balancer or proxy server to load balance? |
| Answer |
| its depends on your apps/device config and setup however proxy is basically for access restriction and load balancer act for your r/w accessibility.. |
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| Question |
| Is it a hardware load balancer ? |
| Answer |
| No its a software load balancer bind with H/w path |
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| Question |
| How do we implement a Load Balancer? |
| Answer |
| you can go with two options…one is storage load balancer and here I am taking about OS load balancer i.e DM on Linux ..for this you need to enable multipathd daemon and in its configuration file need to mentioned wwid of devices and restart the services |
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| Question |
| Breif concept of Load balancing. How it will be helpful ? |
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| Answer |
| It will help you from failure of HBA host /Controler and switch because your SAN connected LUN or device will mapped on multiple paths on single disk so that if you have 2/4 paths on single disk any of path fail or not work inthat case through other path you can access the disk data without any interruption else single path disk failure will have impact the data access or I/Os load on single path will may get slow the access instead of multi paths enabled. |
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| Question |
| Is this os based ? |
| Answer |
| Yes its OS based ..no extra cost is involved |
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| Question |
| is it like OS resolving ips as in dns entries in round robbin fashion? |
| Answer |
| its have three modes of load balancing mechanism.. 1> RR –round robin fashion in the paths 2> SST– shortest service time of the paths 3> SQL– Shortest queue length of the paths |
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| Question |
| Brief us about DM Load Balancer? |
| Answer |
| load balancer can help you to access the disk from failure of paths distributes Data/I/Os between all paths or group of paths active/active or active /passive mode as a admin you will see one logical path binding with all virtual paths based on HBA and storage controller. |
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| Question |
| How fail over is checked ? Is it through any kind of health checker? |
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| Answer |
| multipath daemon is continuously monitoring /checking the path status #multipath -ll command will show you the active/guest or inactive paths detaisl |
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| Question |
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| Is it possible to implement to B/W active – active servers ? If yes how exactly it will work. On which basis it will load ? |
| Answer |
| Question id not clear to me ..please call me off line to clear your doubt.. |
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| Question |
| Is it can be used for multi master ldap load balancing? |
| Answer |
| Ldap is not OS its a DS hence its difference from it |
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| Question |
| What are the pre-requesties required to implement Load Balancer? |
| Answer |
| you need to check DM-mpath package inbuilt in OS or not with SAN connected Devices only ..nothing extra need else only package need to be installed in OS |
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| Question |
| On what basis device mapper is working, Kindly elaborate. |
| Answer |
| When new devices are brought under the control of DM-Multipath, the new devices may be seen in three different places under the /dev directory: /dev/mapper/mpathn, /dev/mpath/mpathn, and /dev/dm-n. The devices in /dev/mapper are created early in the boot process. Use these devices to access the multipathed devices, for example when creating logical volumes. |
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| Question |
| In which platform we are highly using and utilizing LB ? |
| Answer |
| You can use it in any platform but LB is OS/Storage specific not platform specific. |
