We limit the number of concurrent blob downloads per node and per recovery, but if a user configures too many concurrent recoveries they may run out of per-node download permits which yields the following message:

> Unable to acquire permit to use snapshot files during recovery, this recovery will recover index files from the source node. Ensure snapshot files can be used during recovery by setting [indices.recovery.max_concurrent_snapshot_file_downloads] to be no greater than [25]

The `[25]` here is wrong, the 25 permits are shared across all inbound recoveries so we should divide the suggested value by `cluster.routing.allocation.node_concurrent_incoming_recoveries`. In extreme cases the user may have configured so many concurrent recoveries that the only reasonable limit is zero, and in that case we should suggest setting `indices.recovery.use_snapshots: false` instead.


server/src/test/java/org/elasticsearch/indices/recovery/RecoverySettingsTests.java
Settings settings = Settings.builder()
            .put(INDICES_RECOVERY_MAX_CONCURRENT_SNAPSHOT_FILE_DOWNLOADS.getKey(), 10)
            .put(INDICES_RECOVERY_MAX_CONCURRENT_SNAPSHOT_FILE_DOWNLOADS_PER_NODE.getKey(), 5)
            .build();
        IllegalArgumentException exception = expectThrows(
            IllegalArgumentException.class,
            () -> new RecoverySettings(settings, clusterSettings)
        );
        assertThat(
            exception.getMessage(),
            containsString(
                "[indices.recovery.max_concurrent_snapshot_file_downloads_per_node]=5 "
                    + "is less than [indices.recovery.max_concurrent_snapshot_file_downloads]=10"
            )
        );
    }
    public void testAvailableBandwidthsSettingsAreAllConfigured() {
        final NodeRecoverySettings recoverySettings = nodeRecoverySettings();
        recoverySettings.withRandomIndicesRecoveryMaxBytesPerSec();
        recoverySettings.withRoles(randomDataNodeRoles());
        recoverySettings.withRandomMemory();
        final List<Setting<?>> randomSettings = randomSubsetOf(
            randomIntBetween(1, NODE_BANDWIDTH_RECOVERY_SETTINGS.size() - 1),
            NODE_BANDWIDTH_RECOVERY_SETTINGS
        );
        for (Setting<?> setting : randomSettings) {
            if (setting.getKey().equals(NODE_BANDWIDTH_RECOVERY_NETWORK_SETTING.getKey())) {
                recoverySettings.withNetworkBandwidth(randomNonZeroByteSizeValue());
            } else if (setting.getKey().equals(NODE_BANDWIDTH_RECOVERY_DISK_READ_SETTING.getKey())) {
                recoverySettings.withDiskReadBandwidth(randomNonZeroByteSizeValue());