7 ms·

> bloat their io buffer size to several GiB, set the eviction priority to 1 How do you tweak these? I'm aware of dirty_writeback_centisecs and the likes, but y

by jimis 3y ago

> bloat their io buffer size to several GiB, set the eviction priority to 1 How do you tweak these? I'm aware of dirty_writeback_centisecs and the likes, but you are most likely referring to something different.

mattpallissard 3y ago
No, you're thinking along the right lines. These things are kernel tune ables. If you thumb through the sysfs kernel docs you can find loads of options on this sort of thing.
the8472 3y ago
YOLO mountflags for ext4 that minimize synchronous writes: data=writeback,journal_async_commit,lazytime,nobarrier,commit=99999 Good for caches, scratch space, build dirs and anything that can be rebuilt from other data but it'll get corrupted during any non-graceful shutdown. overlayfs offers an even more aggressive mount option "volatile" which ignores all O_SYNC or fsyncs, but no other filesystem exposes that tradeoff.
- Joel_Mckay 3y ago
  Have a look at dedicated external journal disk performance for ext4. It actually is pretty fast, and relatively safe. I find performance wise, a logging fs like f2fs is actually not as terrible as one would expect for most use-cases: UUID=abc /home f2fs defaults,noatime,nodiratime,noquota,discard,nobarrier,inline_xattr,inline_data 0 2
Joel_Mckay 3y ago
These settings heavily depends on your OS, hardware, and use-case. This profile is what I prefer for AORUS 5/RTX3070/i7-12700H/16GB laptops, and despite how terrible the OEM hardware is... this setup will run acceptably well with dual Intel 670p M.2 drives. The following should work with most Debian variants, but is hardly optimal for every platform. But if your laptop is similar, than it should be a good place to start. One caveat, when ejecting media it may take some time to flush your buffers. sudo nano /etc/sysctl.conf net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1 # Ignore ICMP broadcast requests net.ipv4.icmp_echo_ignore_broadcasts = 1 # Disable source packet routing net.ipv4.conf.all.accept_source_route = 0 net.ipv6.conf.all.accept_source_route = 0 net.ipv4.conf.default.accept_source_route = 0 net.ipv6.conf.default.accept_source_route = 0 # Ignore send redirects net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.default.send_redirects = 0 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_max_syn_backlog = 2048 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_syn_retries = 5 net.ipv4.conf.all.log_martians = 1 net.ipv4.icmp_ignore_bogus_error_responses = 1 net.ipv4.conf.all.accept_redirects = 0 net.ipv6.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 net.ipv6.conf.default.accept_redirects = 0 net.ipv4.icmp_echo_ignore_all = 1 #ban list mem net.core.rmem_default=8388608 net.core.wmem_default=8388608 #prevent TCP hijack in older kernels net.ipv4.tcp_challenge_ack_limit = 999999999 #may be needed to reduce failed TCP links net.ipv4.tcp_timestamps=0 net.ipv4.tcp_rfc1337=1 net.ipv4.tcp_workaround_signed_windows=1 net.ipv4.tcp_fack=1 net.ipv4.tcp_low_latency=1 net.ipv4.ip_no_pmtu_disc = 0 net.ipv4.tcp_sack = 1 net.ipv4.tcp_mtu_probing = 1 net.ipv4.tcp_frto=2 net.ipv4.tcp_frto_response=2 net.ipv4.tcp_congestion_control = cubic net.ipv4.tcp_window_scaling = 1 kernel.exec-shield=1 kernel.randomize_va_space=1 #reboot on kernel panic after 20 sec kernel.panic=20 vm.swappiness=1 vm.vfs_cache_pressure=50 #percentage of system memory that can be filled with dirty pages # run to check io performance with: sudo vmstat 1 20 vm.dirty_background_ratio=60 #maximum amount of system memory filled with dirty pages before committed vm.dirty_ratio=80 vm.dirty_background_bytes=2684354560 vm.dirty_bytes=5368709120 #how often the flush processes wake up and check vm.dirty_writeback_centisecs=10000 #how long something can be in cache before it needs to be written vm.dirty_expire_centisecs=60000 vm.min_free_kbytes = 16384 # increase system file descriptor limit fs.file-max=120000 #CONNTRACK_MAX = RAMSIZE (in bytes) / 16384 / (number_of_bits_in_a_pointer / 32) #low power CPU should halve mem usage limits net.ipv4.netfilter.ip_conntrack_max = 16384 net.netfilter.nf_conntrack_max = 16384 net.nf_conntrack_max = 16384 net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 86400 kernel.pid_max = 32767 net.ipv4.ip_local_port_range = 2000 65000

by jimis 3y ago

mattpallissard 3y ago

No, you're thinking along the right lines. These things are kernel tune ables. If you thumb through the sysfs kernel docs you can find loads of options on this sort of thing.

the8472 3y ago

YOLO mountflags for ext4 that minimize synchronous writes: data=writeback,journal_async_commit,lazytime,nobarrier,commit=99999 Good for caches, scratch space, build dirs and anything that can be rebuilt from other data but it'll get corrupted during any non-graceful shutdown. overlayfs offers an even more aggressive mount option "volatile" which ignores all O_SYNC or fsyncs, but no other filesystem exposes that tradeoff.

Joel_Mckay 3y ago
Have a look at dedicated external journal disk performance for ext4. It actually is pretty fast, and relatively safe. I find performance wise, a logging fs like f2fs is actually not as terrible as one would expect for most use-cases: UUID=abc /home f2fs defaults,noatime,nodiratime,noquota,discard,nobarrier,inline_xattr,inline_data 0 2

Joel_Mckay 3y ago

These settings heavily depends on your OS, hardware, and use-case. This profile is what I prefer for AORUS 5/RTX3070/i7-12700H/16GB laptops, and despite how terrible the OEM hardware is... this setup will run acceptably well with dual Intel 670p M.2 drives. The following should work with most Debian variants, but is hardly optimal for every platform. But if your laptop is similar, than it should be a good place to start. One caveat, when ejecting media it may take some time to flush your buffers. sudo nano /etc/sysctl.conf net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1 # Ignore ICMP broadcast requests net.ipv4.icmp_echo_ignore_broadcasts = 1 # Disable source packet routing net.ipv4.conf.all.accept_source_route = 0 net.ipv6.conf.all.accept_source_route = 0 net.ipv4.conf.default.accept_source_route = 0 net.ipv6.conf.default.accept_source_route = 0 # Ignore send redirects net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.default.send_redirects = 0 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_max_syn_backlog = 2048 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_syn_retries = 5 net.ipv4.conf.all.log_martians = 1 net.ipv4.icmp_ignore_bogus_error_responses = 1 net.ipv4.conf.all.accept_redirects = 0 net.ipv6.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 net.ipv6.conf.default.accept_redirects = 0 net.ipv4.icmp_echo_ignore_all = 1 #ban list mem net.core.rmem_default=8388608 net.core.wmem_default=8388608 #prevent TCP hijack in older kernels net.ipv4.tcp_challenge_ack_limit = 999999999 #may be needed to reduce failed TCP links net.ipv4.tcp_timestamps=0 net.ipv4.tcp_rfc1337=1 net.ipv4.tcp_workaround_signed_windows=1 net.ipv4.tcp_fack=1 net.ipv4.tcp_low_latency=1 net.ipv4.ip_no_pmtu_disc = 0 net.ipv4.tcp_sack = 1 net.ipv4.tcp_mtu_probing = 1 net.ipv4.tcp_frto=2 net.ipv4.tcp_frto_response=2 net.ipv4.tcp_congestion_control = cubic net.ipv4.tcp_window_scaling = 1 kernel.exec-shield=1 kernel.randomize_va_space=1 #reboot on kernel panic after 20 sec kernel.panic=20 vm.swappiness=1 vm.vfs_cache_pressure=50 #percentage of system memory that can be filled with dirty pages # run to check io performance with: sudo vmstat 1 20 vm.dirty_background_ratio=60 #maximum amount of system memory filled with dirty pages before committed vm.dirty_ratio=80 vm.dirty_background_bytes=2684354560 vm.dirty_bytes=5368709120 #how often the flush processes wake up and check vm.dirty_writeback_centisecs=10000 #how long something can be in cache before it needs to be written vm.dirty_expire_centisecs=60000 vm.min_free_kbytes = 16384 # increase system file descriptor limit fs.file-max=120000 #CONNTRACK_MAX = RAMSIZE (in bytes) / 16384 / (number_of_bits_in_a_pointer / 32) #low power CPU should halve mem usage limits net.ipv4.netfilter.ip_conntrack_max = 16384 net.netfilter.nf_conntrack_max = 16384 net.nf_conntrack_max = 16384 net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 86400 kernel.pid_max = 32767 net.ipv4.ip_local_port_range = 2000 65000