This is a 4-node glusterfs cluster setup as a replica 3 arbiter 1 cluster. I use 512MB shards, reducing fragmentation of VM disks without hurting performance. My disks are all backed by SSDs. Every node has up to 2 bricks on 2 different disks. Every node is an Android TV H96 MAX X3 box running Armbian with disks attached via the USB 3.0 port. I am able to reboot any node without data loss.

Number of Bricks: 2 x (2 + 1) = 6
Transport-type: tcp
Bricks:
Brick1: amlogic1:/mnt/gluster1/brick2
Brick2: amlogic2:/mnt/gluster1/brick2
Brick3: amlogic4:/mnt/arbiter/arb2s1-2 (arbiter)
Brick4: amlogic3:/mnt/gluster1/brick2
Brick5: amlogic4:/mnt/gluster1/brick2
Brick6: amlogic2:/mnt/arbiter/arb2s3-4 (arbiter)

GlusterFS Volume Options
diagnostics.count-fop-hits: on
diagnostics.latency-measurement: on
performance.cache-refresh-timeout: 10
performance.cache-size: 2GB
storage.fips-mode-rchecksum: on
performance.strict-o-direct: on
features.scrub-freq: daily
features.scrub-throttle: lazy
features.scrub: Inactive
features.bitrot: off
storage.batch-fsync-delay-usec: 0
performance.nl-cache-positive-entry: off
performance.parallel-readdir: off
performance.cache-max-file-size: 512MB
cluster.server-quorum-type: server
performance.readdir-ahead: on
network.ping-timeout: 10
features.shard-block-size: 512MB
client.event-threads: 5
server.event-threads: 3
cluster.data-self-heal-algorithm: full
cluster.shd-max-threads: 16
cluster.shd-wait-qlength: 8192
server.allow-insecure: on
features.shard: on
cluster.quorum-type: auto
network.remote-dio: on
cluster.eager-lock: enable
performance.io-cache: off
performance.read-ahead: off
performance.quick-read: off
cluster.locking-scheme: granular
performance.low-prio-threads: 20
cluster.choose-local: off
features.cache-invalidation-timeout: 600
performance.stat-prefetch: on
performance.cache-invalidation: on
performance.md-cache-timeout: 10
network.inode-lru-limit: 32768
cluster.self-heal-window-size: 8
cluster.granular-entry-heal: enable
transport.address-family: inet
nfs.disable: on
performance.client-io-threads: on


And a custom sysctl.d config:
#/etc/sysctl.d/999-gluster-tuning.conf
vm.admin_reserve_kbytes = 8192
vm.compact_unevictable_allowed = 1
vm.compaction_proactiveness = 20
vm.dirty_background_bytes = 0
vm.dirty_background_ratio = 5
vm.dirty_bytes = 0
vm.dirty_expire_centisecs = 3000
vm.dirty_ratio = 5
vm.dirty_writeback_centisecs = 500
vm.dirtytime_expire_seconds = 3600
vm.extfrag_threshold = 500
vm.hugetlb_shm_group = 0
vm.laptop_mode = 0
vm.legacy_va_layout = 0
vm.lowmem_reserve_ratio = 32 32 32 0
vm.max_map_count = 65530
vm.memory_failure_early_kill = 0
vm.memory_failure_recovery = 1
vm.min_free_kbytes = 36200
vm.mmap_min_addr = 65536
vm.mmap_rnd_bits = 18
vm.mmap_rnd_compat_bits = 11
vm.nr_hugepages = 0
vm.nr_overcommit_hugepages = 0
vm.oom_dump_tasks = 1
vm.oom_kill_allocating_task = 0
vm.overcommit_kbytes = 0
vm.overcommit_memory = 1
vm.overcommit_ratio = 50
vm.page-cluster = 3
vm.page_lock_unfairness = 5
vm.panic_on_oom = 1
vm.percpu_pagelist_high_fraction = 0
vm.stat_interval = 1
vm.swappiness = 10
vm.user_reserve_kbytes = 128364
vm.vfs_cache_pressure = 50
vm.watermark_boost_factor = 15000
vm.watermark_scale_factor = 10