8.10. Configuring Memory Policy for Storage Services¶
You can configure memory limits and guarantees for storage services at runtime using the vinfra memory-policy vstorage-services commands. You can do this for the entire cluster or a specific node.
The following memory parameters can be configured manually:
- memory guarantee
- swap size
- page cache (which, in turn, is set using cache ratio, minimum, and maximum)
Page cache is calculated according to the following formula:
$PAGE_CACHE = minimum <= ratio * $TOTAL_MEMORY <= maximum
The minimum and maximum values are hard limits that are applied if the ratio * $TOTAL_MEMORY value is outside these limits.
To better understand how page cache size is calculated, consider the following examples:
Example 1 (cache size is within limits) |
Example 2 (cache size equals minimum) |
Example 3 (cache size equals maximum) |
|
|---|---|---|---|
| Total memory | 4 GiB | 4 GiB | 4 GiB |
| Cache ratio | 0.5 | 0.1 | 0.9 |
| Cache minimum | 1 GiB | 2 GiB | 1 GiB |
| Cache maximum | 3 GiB | 3 GiB | 3 GiB |
| Cache size | 2 GiB | 2 GiB | 3 GiB |
If memory parameters are set both per node and per cluster, the per-node ones are applied. If no memory parameters are configured manually, the memory management is performed automatically by the vcmmd daemon as follows:
- Each CS (e.g., storage disk) requires 512 MiB of RAM for page cache.
- The page cache minimum is 1 GiB.
- If the total memory is less than 48 GiB, the page cache maximum is calculated as two-thirds of it.
- If the total memory is greater than 48 GiB, the page cache maximum is 32 GiB.
To check the current memory parameters for storage services set by vcmmd, run
# vcmmdctl list
name type active guarantee limit swap cache
<...>
vstorage.slice/vstorage-services.slice SRVC yes 1310720 24522132 0 1048576
8.10.1. vinfra memory-policy vstorage-services per-cluster change¶
Change per-cluster memory parameters:
usage: vinfra memory-policy vstorage-services per-cluster change
[--guarantee <guarantee>] [--swap <swap>] [--cache-ratio <cache-ratio>
--cache-minimum <cache-minimum> --cache-maximum <cache-maximum>]
--guarantee <guarantee>- Guarantee, in bytes
--swap <swap>- Swap size, in bytes, or -1 if unlimited
--cache-ratio <cache-ratio>- Cache ratio from 0 to 1 inclusive
--cache-minimum <cache-minimum>- Minimum cache, in bytes
--cache-maximum <cache-maximum>- Maximum cache, in bytes
Example:
# vinfra memory-policy vstorage-services per-cluster change --guarantee 8796093022208 \
--swap 1099511627776 --cache-ratio 0.5 --cache-minimum 1099511627776 \
--cache-maximum 3298534883328
+-----------+------------------------+
| Field | Value |
+-----------+------------------------+
| cache | maximum: 3298534883328 |
| | minimum: 1099511627776 |
| | ratio: 0.5 |
| guarantee | 8796093022208 |
| swap | 1099511627776 |
+-----------+------------------------+
This command sets the storage services memory parameters for all nodes in the storage cluster as follows:
- the memory guarantee to 8 GB
- the swap size to 1 GB
- the page cache limits: the minimum to 1 GB, the maximum to 3 GB, and the cache ratio to 0.5
8.10.2. vinfra memory-policy vstorage-services per-cluster show¶
Show per-cluster memory parameters:
usage: vinfra memory-policy vstorage-services per-cluster show
Example:
# vinfra memory-policy vstorage-services per-cluster show
+-----------+------------------------+
| Field | Value |
+-----------+------------------------+
| cache | maximum: 3298534883328 |
| | minimum: 1099511627776 |
| | ratio: 0.5 |
| guarantee | 8796093022208 |
| swap | 1099511627776 |
+-----------+------------------------+
This command lists the storage services memory parameters for all nodes in the storage cluster.
8.10.3. vinfra memory-policy vstorage-services per-cluster reset¶
Reset per-cluster parameters to default:
usage: vinfra memory-policy vstorage-services per-cluster reset [--guarantee]
[--swap] [--cache]
--guarantee- Reset only the guarantee.
--swap- Reset only the swap size.
--cache- Reset only cache values.
Example:
# vinfra memory-policy vstorage-services per-cluster reset --cache
+-----------+---------------+
| Field | Value |
+-----------+---------------+
| cache | |
| guarantee | 8796093022208 |
| swap | 1099511627776 |
+-----------+---------------+
This command resets the manually configured page cache limits to default for all nodes in the storage cluster.
8.10.4. vinfra memory-policy vstorage-services per-node change¶
Change per-node memory parameters:
usage: vinfra memory-policy vstorage-services per-node change [--guarantee <guarantee>]
[--swap <swap>] [--cache-ratio <cache-ratio> --cache-minimum <cache-minimum>
--cache-maximum <cache-maximum>] --node <node>
--guarantee <guarantee>- Guarantee, in bytes
--swap <swap>- Swap size, in bytes, or -1 if unlimited
--cache-ratio <cache-ratio>- Cache ratio from 0 to 1 inclusive
--cache-minimum <cache-minimum>- Minimum cache, in bytes
--cache-maximum <cache-maximum>- Maximum cache, in bytes
--node <node>- Node ID or hostname
Example:
# vinfra memory-policy vstorage-services per-node change --guarantee 8796093022208 \
--swap 1099511627776 --cache-ratio 0.5 --cache-minimum 1099511627776 \
--cache-maximum 3298534883328 --node 7ffa9540-5a20-41d1-b203-e3f349d62565
+-----------+------------------------+
| Field | Value |
+-----------+------------------------+
| cache | maximum: 3298534883328 |
| | minimum: 1099511627776 |
| | ratio: 0.5 |
| guarantee | 8796093022208 |
| swap | 1099511627776 |
+-----------+------------------------+
This command sets the storage services memory parameters for the node with the ID 7ffa9540-5a20-41d1-b203-e3f349d62565 as follows:
- the memory guarantee to 8 GB
- the swap size to 1 GB
- the page cache limits: the minimum to 1 GB, the maximum to 3 GB, and the cache ratio to 0.5
8.10.5. vinfra memory-policy vstorage-services per-node show¶
Show per-node memory parameters:
usage: vinfra memory-policy vstorage-services per-node show --node <node>
--node <node>- Node ID or hostname
Example:
# vinfra memory-policy vstorage-services per-node show \
--node 7ffa9540-5a20-41d1-b203-e3f349d62565
+-----------+-------------------------+
| Field | Value |
+-----------+-------------------------+
| cache | maximum: 13194139533312 |
| | minimum: 8796093022208 |
| | ratio: 0.7 |
| guarantee | 8796093022208 |
| swap | 1099511627776 |
+-----------+-------------------------+
This command lists the storage services memory parameters set for the node with the ID 7ffa9540-5a20-41d1-b203-e3f349d62565.
8.10.6. vinfra memory-policy vstorage-services per-node reset¶
Reset per-node memory parameters to defaults:
usage: vinfra memory-policy vstorage-services per-node reset [--guarantee] [--swap]
[--cache] --node <node>
--guarantee- Reset only the guarantee.
--swap- Reset only the swap size.
--cache- Reset only the cache values.
--node <node>- Node ID or hostname
Example:
# vinfra memory-policy vstorage-services per-node reset --cache \
--node 7ffa9540-5a20-41d1-b203-e3f349d62565
+-----------+---------------+
| Field | Value |
+-----------+---------------+
| cache | |
| guarantee | 8796093022208 |
| swap | 1099511627776 |
+-----------+---------------+
This command resets the manually configured page cache limits to default for the node with the ID 7ffa9540-5a20-41d1-b203-e3f349d62565.