Saya punya satu file 50 GB di server_A, dan saya menyalinnya ke server_B. saya berlari
server_A$ rsync --partial --progress --inplace --append-verify 50GB_file root@server_B:50GB_file
Server_B memiliki 32 GB RAM dengan 2 GB swap. Sebagian besar tidak digunakan dan seharusnya memiliki banyak RAM gratis. Ini memiliki banyak ruang disk. Pada sekitar 32 GB, transfer dibatalkan karena sisi jarak jauh menutup koneksi.
Server_B sekarang telah meninggalkan jaringan. Kami meminta pusat data untuk reboot. Ketika saya melihat log kernel dari sebelum crash, saya melihat bahwa itu menggunakan 0 byte swap, dan daftar proses menggunakan memori sangat sedikit (proses rsync terdaftar menggunakan 600 KB RAM), tetapi oom_killer adalah menjadi liar, dan hal terakhir dalam log adalah di mana ia membunuh proses pembaca kernel metalog.
Ini adalah kernel 3.2.59, 32-bit (jadi tidak ada proses yang dapat memetakan lebih dari 4 GB).
Ini hampir seolah-olah Linux memberikan prioritas lebih untuk caching daripada daemon berjalan lama. Apa yang memberi ?? Dan bagaimana saya bisa menghentikannya agar tidak terjadi lagi?
Ini adalah output dari oom_killer:
Sep 23 02:04:16 [kernel] [1772321.850644] clamd invoked oom-killer: gfp_mask=0x84d0, order=0, oom_adj=0, oom_score_adj=0
Sep 23 02:04:16 [kernel] [1772321.850649] Pid: 21832, comm: clamd Tainted: G C 3.2.59 #21
Sep 23 02:04:16 [kernel] [1772321.850651] Call Trace:
Sep 23 02:04:16 [kernel] [1772321.850659] [<c01739ac>] ? dump_header+0x4d/0x160
Sep 23 02:04:16 [kernel] [1772321.850662] [<c0173bf3>] ? oom_kill_process+0x2e/0x20e
Sep 23 02:04:16 [kernel] [1772321.850665] [<c0173ff8>] ? out_of_memory+0x225/0x283
Sep 23 02:04:16 [kernel] [1772321.850668] [<c0176438>] ? __alloc_pages_nodemask+0x446/0x4f4
Sep 23 02:04:16 [kernel] [1772321.850672] [<c0126525>] ? pte_alloc_one+0x14/0x2f
Sep 23 02:04:16 [kernel] [1772321.850675] [<c0185578>] ? __pte_alloc+0x16/0xc0
Sep 23 02:04:16 [kernel] [1772321.850678] [<c0189e74>] ? vma_merge+0x18d/0x1cc
Sep 23 02:04:16 [kernel] [1772321.850681] [<c01856fa>] ? handle_mm_fault+0xd8/0x15d
Sep 23 02:04:16 [kernel] [1772321.850685] [<c012305a>] ? do_page_fault+0x20e/0x361
Sep 23 02:04:16 [kernel] [1772321.850688] [<c018a9c4>] ? sys_mmap_pgoff+0xa2/0xc9
Sep 23 02:04:16 [kernel] [1772321.850690] [<c0122e4c>] ? vmalloc_fault+0x237/0x237
Sep 23 02:04:16 [kernel] [1772321.850694] [<c08ba7e6>] ? error_code+0x5a/0x60
Sep 23 02:04:16 [kernel] [1772321.850697] [<c08b0000>] ? cpuid4_cache_lookup_regs+0x372/0x3b2
Sep 23 02:04:16 [kernel] [1772321.850700] [<c0122e4c>] ? vmalloc_fault+0x237/0x237
Sep 23 02:04:16 [kernel] [1772321.850701] Mem-Info:
Sep 23 02:04:16 [kernel] [1772321.850703] DMA per-cpu:
Sep 23 02:04:16 [kernel] [1772321.850704] CPU 0: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850706] CPU 1: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850707] CPU 2: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850709] CPU 3: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850711] CPU 4: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850713] CPU 5: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850714] CPU 6: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850716] CPU 7: hi: 0, btch: 1 usd: 0
Sep 23 02:04:16 [kernel] [1772321.850718] Normal per-cpu:
Sep 23 02:04:16 [kernel] [1772321.850719] CPU 0: hi: 186, btch: 31 usd: 70
Sep 23 02:04:16 [kernel] [1772321.850721] CPU 1: hi: 186, btch: 31 usd: 116
Sep 23 02:04:16 [kernel] [1772321.850723] CPU 2: hi: 186, btch: 31 usd: 131
Sep 23 02:04:16 [kernel] [1772321.850724] CPU 3: hi: 186, btch: 31 usd: 76
Sep 23 02:04:16 [kernel] [1772321.850726] CPU 4: hi: 186, btch: 31 usd: 29
Sep 23 02:04:16 [kernel] [1772321.850728] CPU 5: hi: 186, btch: 31 usd: 61
Sep 23 02:04:16 [kernel] [1772321.850731] CPU 7: hi: 186, btch: 31 usd: 17
Sep 23 02:04:16 [kernel] [1772321.850733] HighMem per-cpu:
Sep 23 02:04:16 [kernel] [1772321.850734] CPU 0: hi: 186, btch: 31 usd: 2
Sep 23 02:04:16 [kernel] [1772321.850736] CPU 1: hi: 186, btch: 31 usd: 69
Sep 23 02:04:16 [kernel] [1772321.850738] CPU 2: hi: 186, btch: 31 usd: 25
Sep 23 02:04:16 [kernel] [1772321.850739] CPU 3: hi: 186, btch: 31 usd: 27
Sep 23 02:04:16 [kernel] [1772321.850741] CPU 4: hi: 186, btch: 31 usd: 7
Sep 23 02:04:16 [kernel] [1772321.850743] CPU 5: hi: 186, btch: 31 usd: 188
Sep 23 02:04:16 [kernel] [1772321.850744] CPU 6: hi: 186, btch: 31 usd: 25
Sep 23 02:04:16 [kernel] [1772321.850746] CPU 7: hi: 186, btch: 31 usd: 158
Sep 23 02:04:16 [kernel] [1772321.850750] active_anon:117913 inactive_anon:9942 isolated_anon:0
Sep 23 02:04:16 [kernel] [1772321.850751] active_file:106466 inactive_file:7784521 isolated_file:0
Sep 23 02:04:16 [kernel] [1772321.850752] unevictable:40 dirty:0 writeback:61 unstable:0
Sep 23 02:04:16 [kernel] [1772321.850753] free:143494 slab_reclaimable:128312 slab_unreclaimable:4089
Sep 23 02:04:16 [kernel] [1772321.850754] mapped:6706 shmem:308 pagetables:915 bounce:0
Sep 23 02:04:16 [kernel] [1772321.850759] DMA free:3624kB min:140kB low:172kB high:208kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolate
d(file):0kB present:15808kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:240kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tm
p:0kB pages_scanned:0 all_unreclaimable? yes
Sep 23 02:04:16 [kernel] [1772321.850763] lowmem_reserve[]: 0 869 32487 32487
Sep 23 02:04:16 [kernel] [1772321.850770] Normal free:8056kB min:8048kB low:10060kB high:12072kB active_anon:0kB inactive_anon:0kB active_file:248kB inactive_file:388kB unevictable:0kB isolated(anon)
:0kB isolated(file):0kB present:890008kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:513008kB slab_unreclaimable:16356kB kernel_stack:1888kB pagetables:3660kB unstable:0
kB bounce:0kB writeback_tmp:0kB pages_scanned:1015 all_unreclaimable? yes
Sep 23 02:04:16 [kernel] [1772321.850774] lowmem_reserve[]: 0 0 252949 252949
Sep 23 02:04:16 [kernel] [1772321.850785] lowmem_reserve[]: 0 0 0 0
Sep 23 02:04:16 [kernel] [1772321.850788] DMA: 0*4kB 7*8kB 3*16kB 6*32kB 4*64kB 6*128kB 5*256kB 2*512kB 0*1024kB 0*2048kB 0*4096kB = 3624kB
Sep 23 02:04:16 [kernel] [1772321.850795] Normal: 830*4kB 80*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 1*4096kB = 8056kB
Sep 23 02:04:16 [kernel] [1772321.850802] HighMem: 13*4kB 14*8kB 2*16kB 2*32kB 0*64kB 0*128kB 2*256kB 2*512kB 3*1024kB 0*2048kB 136*4096kB = 561924kB
Sep 23 02:04:16 [kernel] [1772321.850809] 7891360 total pagecache pages
Sep 23 02:04:16 [kernel] [1772321.850811] 0 pages in swap cache
Sep 23 02:04:16 [kernel] [1772321.850812] Swap cache stats: add 0, delete 0, find 0/0
Sep 23 02:04:16 [kernel] [1772321.850814] Free swap = 1959892kB
Sep 23 02:04:16 [kernel] [1772321.850815] Total swap = 1959892kB
Sep 23 02:04:16 [kernel] [1772321.949081] 8650736 pages RAM
Sep 23 02:04:16 [kernel] [1772321.949084] 8422402 pages HighMem
Sep 23 02:04:16 [kernel] [1772321.949085] 349626 pages reserved
Sep 23 02:04:16 [kernel] [1772321.949086] 7885006 pages shared
Sep 23 02:04:16 [kernel] [1772321.949087] 316864 pages non-shared
Sep 23 02:04:16 [kernel] [1772321.949089] [ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name
(rest of process list omitted)
Sep 23 02:04:16 [kernel] [1772321.949656] [14579] 0 14579 579 171 5 0 0 rsync
Sep 23 02:04:16 [kernel] [1772321.949662] [14580] 0 14580 677 215 5 0 0 rsync
Sep 23 02:04:16 [kernel] [1772321.949669] [21832] 113 21832 42469 37403 0 0 0 clamd
Sep 23 02:04:16 [kernel] [1772321.949674] Out of memory: Kill process 21832 (clamd) score 4 or sacrifice child
Sep 23 02:04:16 [kernel] [1772321.949679] Killed process 21832 (clamd) total-vm:169876kB, anon-rss:146900kB, file-rss:2712kB
Ini adalah output 'top' setelah mengulangi perintah rsync saya sebagai pengguna non-root:
top - 03:05:55 up 8:43, 2 users, load average: 0.04, 0.08, 0.09
Tasks: 224 total, 1 running, 223 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0% us, 0.0% sy, 0.0% ni, 99.9% id, 0.0% wa, 0.0% hi, 0.0% si
Mem: 33204440k total, 32688600k used, 515840k free, 108124k buffers
Swap: 1959892k total, 0k used, 1959892k free, 31648080k cached
Berikut adalah parameter sysctl vm:
# sysctl -a | grep '^vm'
vm.overcommit_memory = 0
vm.panic_on_oom = 0
vm.oom_kill_allocating_task = 0
vm.oom_dump_tasks = 1
vm.overcommit_ratio = 50
vm.page-cluster = 3
vm.dirty_background_ratio = 1
vm.dirty_background_bytes = 0
vm.dirty_ratio = 0
vm.dirty_bytes = 15728640
vm.dirty_writeback_centisecs = 500
vm.dirty_expire_centisecs = 3000
vm.nr_pdflush_threads = 0
vm.swappiness = 60
vm.lowmem_reserve_ratio = 256 32 32
vm.drop_caches = 0
vm.min_free_kbytes = 8192
vm.percpu_pagelist_fraction = 0
vm.max_map_count = 65530
vm.laptop_mode = 0
vm.block_dump = 0
vm.vfs_cache_pressure = 100
vm.legacy_va_layout = 0
vm.stat_interval = 1
vm.mmap_min_addr = 4096
vm.vdso_enabled = 2
vm.highmem_is_dirtyable = 0
vm.scan_unevictable_pages = 0