search for: dirty_background_ratio

...When I try to transfer huge files above (100MB) from a client on to the USB hard disk, I find that the page cache eats up almost about 100MB and occasionally the system runs out of memory. I even tried tweaking the /proc/sys/vm settings with the following values, but it did not help. /proc/sys/vm/dirty_background_ratio = 2 /proc/sys/vm/dirty_ratio = 5 /proc/sys/vm/dirty_expire_centisecs = 1000 /proc/sys/vm/vfs_cache_pressure = 10000 I also tried copying the huge file locally from one folder to another through the USB interface using dd oflag=direct flag (unbuffered write). But the page cache again ate away ab...

we're having a weird disk I/O problem on a 5.4 server connected to an external SAS storage with an LSI logic megaraid sas 1078. The server is used as a samba file server. Every time we try to copy some large file to the storage-based file system, the disk utilization see-saws up to 100% to several seconds of inactivity, to climb up again to 100% and so forth. Here are a snip from the iostat

I've had a few systems with a lot of RAM and very busy filesystems come up with filesystem errors that took a manual 'fsck -y' after what should have been a clean reboot. This is particularly annoying on remote systems where I have to talk someone else through the recovery. Is there some time limit on the cache write with a 'reboot' (no options) command or is ext4 that

...g served are RAID-5 sets with write-back cache enabled (BBU is good). RAID controller logs are free of errors. NFS servers used dual bonded gigabit links in balance-alb mode. Turning off one interface in the bond made no difference. Relevant /etc/sysctl.conf parameters: vm.dirty_ratio = 50 vm.dirty_background_ratio = 1 vm.dirty_expire_centisecs = 1000 vm.dirty_writeback_centisecs = 100 vm.min_free_kbytes = 65536 net.core.rmem_default = 262144 net.core.rmem_max = 262144 net.core.wmem_default = 262144 net.core.wmem_max = 262144 net.core.netdev_max_backlog = 25000 net.ipv4.tcp_reordering = 127 net.ipv4.tcp_rmem...

...Is there some time limit on the cache write with a 'reboot' (no > options) command or is ext4 that fragile? I'd say there's no limit in the amount of time the kernel waits until the blocks have been written to disk; driven by there parameters: vm.dirty_background_bytes = 0 vm.dirty_background_ratio = 10 vm.dirty_bytes = 0 vm.dirty_expire_centisecs = 3000 vm.dirty_ratio = 20 vm.dirty_writeback_centisecs = 500 ie, if the data cached on RAM is older than 30s or larger than 10% available RAM, the kernel will try to flush it to disk. Depending how much data needs to be flushed at poweroff/reboot...

...b6f - GlusterFS: 3.4.0-8.el6 - Sysctl.conf: > vm.swappiness = 0 > vm.vfs_cache_pressure = 1000 > net.core.rmem_max = 4096000 > net.core.wmem_max = 4096000 > net.ipv4.neigh.default.gc_thresh2 = 2048 > net.ipv4.neigh.default.gc_thresh3 = 4096 > vm.dirty_background_ratio = 1 > vm.dirty_ratio = 16 I use only default config for GlusterFS (follow http://gluster.org/community/documentation/index.php/Getting_started_overview). After testing between NFS client and FUSE client, I choose NFS because the performance is much better. NFS mount options: svr385-1212.l...

...e Linux VM will buffer write data in the kernel buffer cache until it runs out of memory for that (vm.dirty_ratio), then it will freeze any process that issues the writes. If your VM has a lot of memory relative to storage speed, this can result in very long delays. Try reducing Linux kernel vm.dirty_background_ratio to get writes going sooner and vm.dirty_ratio so that the freezes don't last as long. You can even reduce VM's block device queue depth. But most of all make sure that gluster writes are performing near a typical local block device speed. > > Does glusterfs have any tuning options,...

...all.log_martians = 0 net.ipv4.conf.default.log_martians = 0 net.ipv4.conf.default.accept_source_route = 0 net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 vm.vfs_cache_pressure = 35 vm.nr_hugepages = 512 net.ipv4.tcp_max_syn_backlog = 2048 fs.aio-max-nr = 1048576 vm.dirty_background_ratio = 3 vm.dirty_ratio = 40 After making changes, do you have any recommendations on which tools to use to monitor those changes and see how they perform? I have noatime set in fstab in the guest for the /var partition, where much of the spamassassin occurs. I've included below my libvirt xml c...

...his is part of a database bulkload ...after finish , integrity will be desirable (not a obligation, since this is a test environment) For now, performance is the mainly requirement... A plus : root@jdivm06:/proc/sys/fs# cat /proc/sys/vm/dirty_ratio 50 root@jdivm06:/proc/sys/fs# cat /proc/sys/vm/dirty_background_ratio 10 Thanks Cesar -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html

...[ 1200.060576] [<ffffffff8113f352>] ? __generic_file_write_iter+0x132/0x340 ------------------------------------------------------------------------------------------------- * What exactly did you do (or not do) that was effective (or ineffective)? I changed the values of vm.dirty_background_ratio and vm.dirty_ratio, but had no influence * What was the outcome of this action? nothing * What outcome did you expect instead? I expected, the VM does not freeze -- System Information: Debian Release: 8.4 APT prefers stable-updates APT policy: (500, 'stable-updates'...

...ache write with a 'reboot' (no >> options) command or is ext4 that fragile? > > I'd say there's no limit in the amount of time the kernel waits until > the blocks have been written to disk; driven by there parameters: > > vm.dirty_background_bytes = 0 > vm.dirty_background_ratio = 10 > vm.dirty_bytes = 0 > vm.dirty_expire_centisecs = 3000 > vm.dirty_ratio = 20 > vm.dirty_writeback_centisecs = 500 > > ie, if the data cached on RAM is older than 30s or larger than 10% > available RAM, the kernel will try to flush it to disk. Depending how > much data...

...gePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 10232 kB DirectMap2M: 901120 kB sysctl: vm.oom_dump_tasks = 0 vm.oom_kill_allocating_task = 1 vm.panic_on_oom = 1 vm.admin_reserve_kbytes = 8192 vm.block_dump = 0 vm.dirty_background_bytes = 0 vm.dirty_background_ratio = 10 vm.dirty_bytes = 0 vm.dirty_expire_centisecs = 3000 vm.dirty_ratio = 20 vm.dirty_writeback_centisecs = 500 vm.drop_caches = 0 vm.highmem_is_dirtyable = 0 vm.hugepages_treat_as_movable = 0 vm.hugetlb_shm_group = 0 vm.laptop_mode = 0 vm.legacy_va_layout = 0 vm.lowmem_reserve_ratio = 256 32...

I believe 30 sec is the default for the checkpoint interval.  Is this adjustable? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html

Hi, On 03/19/2018 03:42 PM, TomK wrote: > On 3/19/2018 5:42 AM, Ondrej Valousek wrote: > Removing NFS or NFS Ganesha from the equation, not very impressed on my > own setup either.? For the writes it's doing, that's alot of CPU usage > in top. Seems bottle-necked via a single execution core somewhere trying > to facilitate read / writes to the other bricks. > >