Multipath Helper

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This app walks you through the process of creating an optimal configuration for multipath devices on Red Hat Enterprise Linux 5, 6, or 7. The app gives you options to create advanced multipath configurations with custom aliases, device blacklists, and settings for the characteristics of individual multipath devices.

Upon completion, the app will generate an installation script that includes the configuration parameters you selected. It will also present the configuration file, multipath.conf, for review. Once you are satisfied with your configuration simply download the installation script and run it on your server for easy and consistent configuration of your multipath devices.

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Better we check if device-mapper-multipath rpm package is installed before run yum install command, also back up configure file that is modified.

Thank you for the suggestion. However, using yum to install a package that is already installed should have no ill effects. Yum will detect this condition and report...
"Package device-mapper-multipath.N.V.R already installed and latest version"

Are you observing different behavior from yum?

Given all of the possibilities, options, and variables involved in multipathing, I expected a HECK OF A LOT more than just setting user friendly names and running chkconfig.

Setting up aliases and blacklists may be helpful for some, but this is hardly providing an "optimal configuration". Perhaps "bare minimum" or "it's turned on" would be better descriptions.

This is a fabulous idea, please add some substance.

Chaz,

There are, as you mentioned, a wide variety of options for multipath and many are device specific. Can you be more specific as to the global options you typically specify?

Keith

Wow. I had high hopes for this tool.
I expected a lot, lot more. (+1 on Chaz's comments)
For example, I was hoping the default black list would get added if I selected that, but no... you have to retype the entry. You should be able to modify what's there in the web tool.

Bill,
I think you are suggesting that [1] be added by default to the generated multipath.conf file. For RHEL, this should be a compiled in default and is visible in [2].

Is there a specific blacklist configuration that you find useful that is not a compiled in default? Also, we are interested to know what other settings you would like to see exposed in the app.

Keith

[1] "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]"
[2] /usr/share/doc/device-mapper-multipath-
/multipath.conf.defaults

Agree with the previous commenters - very good idea to start with, personally disappointed as I was expecting a lot more.
Was there any kind of vetting? Someone in that process must have commented that it is possible to do a lot more here.

Edit: The last bit sounds critical, I know - please read more as an optimistic observation.

Justin,
Thanks for the feedback. Can you be a bit more specific about the options you would like to see exposed by the app?
Keith

It would be nice if you added vendor specific options. For example you could have an option as to which hardware the user will be running mulipath. If they choose hp blade then you add devnode "^cciss!c[0-9]d[0-9]" to the multipath config to ignore. Another feature that would be nice is choosing the array you will be connecting to. For example add an option to choose EMC then put in the multipath config:
devices {
# Configurazione specifica EMC CLARiiON
device {
vendor "DGC"
product "
"
product_blacklist "LUNZ"
prio alua
path_grouping_policy group_by_prio
features "1 queue_if_no_path"
failback immediate
hardware_handler "1 alua"
}

This is the complexity that needs to be taken out of the process so people new to linux can get the storage up and running without much hassle. It would even be nice to have a TUI built into the OS to configure this.

John,

Thanks for the feedback. We are working upon the suggestion and exploring the use case of providing the user with the device option and selecting the needed parameters.

Hello John,

Based upon your suggestion, we have added a feature wherein the user can select the Multipath Default attribute for the specified device. The default parameters for that selected vendor/product will be enabled and entered into the multipath config file.

e.g. Vendor : HP Product: A6189A

device {
vendor HP
product A6189A
getuid /lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/%n
features 0
hwhandler 0
selector round-robin 0
pgpolicy multipbus
rr_weight RR_WEIGHT_NONE
no_path_retry 12
minio 1000
minio_rq 1000_RQ
checker_name DIRECTIO
prio_name const
}

Please have a try and let us know the feedback.

Okay, since this is a "starting configuration" tool, I was thinking typical (if there is such a thing any more) scenarios. Some options: -
- As posted above - starting options to configure multipath in the recommended way for some common storage vendors (EMC, HP, NetApp etc.)
- Usage cases - multiple adapters same network (recommend grouping and network options to match), multiple adapters different networks etc.
- Blacklist recommendations
- Use of wwids and aliases to make things more readable

Hi Justin,

Thanks for the valuable feedback. Based on your suggestions , we have added the feature to configure the multipath attribute based on default values of common storage vendors.
The selected attribute will be enabled in the multipath.conf file as stated in the e.g. below.

device {
vendor HP
product A6189A
getuid /lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/%n
features 0
hwhandler 0
selector round-robin 0
pgpolicy multipbus
rr_weight RR_WEIGHT_NONE
no_path_retry 12
minio 1000
minio_rq 1000_RQ
checker_name DIRECTIO
prio_name const
}

Please have a try and let us know the feedback.

multipath timeout (polling_interval , no_path_retry) feature is valuable .....

Under the Custom Multipath Attributes: At the end of the line there is misspell of "Multiath.conf"

Fixed the Custom Multipath Attributes Description.

https://access.redhat.com/labs/multipathhelper/#/

I want to know how to resize an existing multipath device, not create an installation script. I have a working multipath.conf file, but when I increase the size of the LUN on the SAN, the new size does not show up in the multipath device. There is no pv created yet for this device. I have done a rescan at the OS level and even removed the devices from the multipath.conf whitelist, did a service multipath reload, added the devices back into the whitelist, did another reload, to no avail. I found a command in the RHEL 5 manuals that held great promise, multipathd -k'resize map mpathb', and when I ran it the output was "ok", so you would think it resized, right? No, it did not. This is the section I am led to when searching for "resize existing multipath device", yet there is no information on how to resize an existing multipath device here.

i am not able to use this feature, as i want to evaluate this app. i have got a 30 days free subscription but when i click on go to application i am redirected to a page saying (An active Red Hat subscription is required to use Customer Portal Labs.). Need help!!!