Hi, im currently testing your multipath solution with the following setup: HP DL585 with 4 DualCore Opterons, 8Gig RAM an 4 Qlogic FC Adapters, connected to 2 IBM DS8100 Storages through two Broadcom Fabrics. i Have 4 LUNS, 2 from each Storage Box. I build 2 SW-Raid´s with 2 LUNS each to get host-based-mirroring. The SW-Raid is used as PV for LVM2. Its a RH4 AS U3 kernel (2.6.9-34) with the device-mapper-multipath 0.45. After doing some Stresstests with bonnie (4 parallel runs) i got the following: Mar 31 10:05:06 arenat11 kernel: bonnie++: page allocation failure. order:0, mode:0x50 Mar 31 10:05:06 arenat11 kernel: Mar 31 10:05:06 arenat11 kernel: Call Trace:<ffffffff8015d06e>{__alloc_pages+846} <ffffffff8015d105>{__get_free_pages+11} Mar 31 10:05:06 arenat11 kernel: <ffffffff801600e4>{kmem_getpages+36} <ffffffff80160879>{cache_alloc_refill+609} Mar 31 10:05:06 arenat11 kernel: <ffffffff801605b7>{kmem_cache_alloc+90} <ffffffffa00a146b>{:jbd:journal_start+132} Mar 31 10:05:06 arenat11 kernel: <ffffffffa00b6ae4>{:ext3:ext3_ordered_writepage+127} Mar 31 10:05:06 arenat11 kernel: <ffffffff801641bb>{shrink_zone+3095} <ffffffff8013f4b7>{del_timer+107} Mar 31 10:05:06 arenat11 kernel: <ffffffff8013f574>{del_singleshot_timer_sync+9} <ffffffff80305528>{schedule_timeout+252 } Mar 31 10:05:06 arenat11 kernel: <ffffffff801647a5>{try_to_free_pages+303} <ffffffff80134df2>{autoremove_wake_function+0 } Mar 31 10:05:06 arenat11 kernel: <ffffffff8015cf74>{__alloc_pages+596} <ffffffff8015a6d8>{generic_file_buffered_write+29 5} Mar 31 10:05:06 arenat11 kernel: <ffffffffa00be568>{:ext3:__ext3_journal_stop+31} <ffffffff8013bd7f>{current_fs_time+89} Mar 31 10:05:06 arenat11 kernel: <ffffffff8015af36>{__generic_file_aio_write_nolock+731} Mar 31 10:05:06 arenat11 kernel: <ffffffff8015b1d4>{generic_file_aio_write_nolock+32} Mar 31 10:05:06 arenat11 kernel: <ffffffff8015b29e>{generic_file_aio_write+126} <ffffffffa00b4ee5>{:ext3:ext3_file_write +22} Mar 31 10:05:06 arenat11 kernel: <ffffffff80177b65>{do_sync_write+173} <ffffffff80304a85>{thread_return+0} Mar 31 10:05:06 arenat11 kernel: <ffffffff80304add>{thread_return+88} <ffffffff80134df2>{autoremove_wake_function+0} Mar 31 10:05:06 arenat11 kernel: <ffffffff80191570>{dnotify_parent+34} <ffffffff80177c60>{vfs_write+207} Mar 31 10:05:06 arenat11 kernel: <ffffffff80177d48>{sys_write+69} <ffffffff801101c6>{system_call+126} Mar 31 10:05:06 arenat11 kernel: Mar 31 10:05:06 arenat11 kernel: Mem-info: Mar 31 10:05:06 arenat11 kernel: Node 3 DMA per-cpu: empty Mar 31 10:05:06 arenat11 kernel: Node 3 Normal per-cpu: Mar 31 10:05:06 arenat11 kernel: cpu 0 hot: low 32, high 96, batch 16 Mar 31 10:05:06 arenat11 kernel: cpu 0 cold: low 0, high 32, batch 16 Mar 31 10:05:06 arenat11 kernel: cpu 1 hot: low 32, high 96, batch 16 Mar 31 10:05:06 arenat11 kernel: cpu 1 cold: low 0, high 32, batch 16 Mar 31 10:05:06 arenat11 kernel: cpu 2 hot: low 32, high 96, batch 16 This only happens if i use device-mapper-multipath for multipathing, it does not if i use the LUNS without. Any Ideas ? I can run additional Test as you like, because this is a test environment. I have two of those boxen, one with 128G of ram, all tests welcome. Greetings from Munich Stefan Majer -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel