Date: Wed, 3 Jul 2013 14:46:09 +0200 From: Maxim Bourmistrov <mxb@unixconn.com> To: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Slow resilvering with mirrored ZIL Message-ID: <CABBFC07-68C2-4F43-9AFC-920D8C34282E@unixconn.com>
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Hello list@, I'm in the middle of replacing my old hard drives with new ones on my = ZFS NAS. There are at least two ways to accomplish this.=20 I'm however, doing resilvering of new ones. While doing a resilvering of one of possible four drivers I had 40-60 = MB/s resilvering speed. ZIL is located on a 10G partition on an Intel SLC SSD. It toke about 24h to resilver about 1.5T. Then I decided to create a 10G partition on another SSD(OCZ AGILITY 3 , = MLC) and created a mirror of ZIL. Done that, I continued to resilver the second drive out of four and = noted significant speed drop of resilvering. 5MB/s as of now. I understand that doing a ZIL mirror will result in performance penalty, = but not that much?! Box is slightly loaded and I tried to completely shutdown all services = and disconnect it from LAN in order to isolate it, without any = improvements in speed. Any ideas? Am I completely wrong in assuming that ZIL is involved in resilvering = process? P.S. SSDs: ada4: <INTEL SSDSA2VP020G2 2CV102M5> ATA-7 SATA 2.x device ada4: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes) ada4: Command Queueing enabled ada4: 19087MB (39091248 512 byte sectors: 16H 63S/T 16383C) ada4: Previously was known as ad12 ada5 at ahcich5 bus 0 scbus5 target 0 lun 0 ada5: <OCZ-AGILITY3 2.15> ATA-8 SATA 3.x device ada5: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes) ada5: Command Queueing enabled ada5: 57241MB (117231408 512 byte sectors: 16H 63S/T 16383C) ada5: Previously was known as ad14
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