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| Points to note when changing the values of the VVR tunables | ||
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| Prev | Tunable parameters for VxVM | Next |
Note the following points when changing the values of the tunables:
When decreasing the value of the vol_rvio_maxpool_sz tunable, all the RVGs on the host must be stopped.
When decreasing the size of the tunables vol_max_rdback_sz and vol_max_nmpool_sz pause the RLINKs.
The vol_min_lowmem_sz tunable is auto-tunable; depending on the incoming writes VVR increases or decreases the tunable value.
Auto-tuning is only supported for the tunable vol_min_lowmem_sz.
In a shared disk group environment, you may choose to set only those tunables that are required on each host. However, we recommend that you configure the tunables appropriately even if the tunables are currently not being used. This is because if the logowner changes, then tunables on the new logowner will be used. The following list of tunables are required to be set only on the logowner and not the other hosts:
vol_max_rdback_sz
vol_max_nmpool_sz
vol_max_wrspool_sz
vol_dcm_replay_size
vol_nm_hb_timeout
vol_vvr_use_nat
The tunable changes that are done using the vxtune command affect only the tunable values on the host on which it is run. Therefore, in a shared disk group environment, you must run the command separately on each host for which you want to change the tunable values.