Date: Wed, 28 Nov 2012 14:29:26 +0100 From: "O. Hartmann" <ohartman@zedat.fu-berlin.de> To: Current FreeBSD <freebsd-current@freebsd.org> Subject: ZFS: ZIL with only one additional disk and how secure? Message-ID: <50B611B6.40903@zedat.fu-berlin.de>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigCB2D0DE8D7C6F9A64D13F248 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hello, I have a naive question. I read about speeding up NFSv4 shared ZFS array. I use a RAIDZ1 volume made up from 5 times 3TB harddrives, attached to a ICH10 SATA controller on a FreeBSD 10.0-CURRENT box. The maximum performance of that array never goes beyond 45 - 51 MB/s and levels out very often at 12 - 35 MB/s when used as a NFSv4 share and 1 GBit LAN. The local system harddisk, attached to the sixth SATA port of the same controller and containig a UFS2 filesystem, is capable of doing tasks with 60 - 80 MB/s (peak) when used as a NFSv4 share with another FreeBSD 10.0-CURRENT box. I used several reported tweaks on the RAIDZ1 ZFS volume exporting it as a NFSv4 volume, so I was capable of raising the throughput from sad 3 MB/s up to the 30 MB/s sustained. Also I was told that adding a dedicated ZIL drive could speed up things up to 90 MB/s with the mentioned construction of a RAIDZ1 over NFSv4. It is always suggested to add SSDs, a pair, for security reasons. My question in conrete is now: Do I need two (2) ZIL drives in a mirror? I guess this is considered due to security issues which lead to the next question: If it is possible to use only one ZIL drive and this drive gets corrupted, is the whole ZFS array corrupted, then? The minor question regards to the use of SSDs: Is it possible to gain speedup also from an ordinary disk dedicated to the ZFS array connected to a additional SATA controller? The SATA controller should be fast enough to serve a bandwith of 90 - 100 MB/s (theoretically) over 1 GBit lines when using the ZFS array as a NFSv4 export (the LAN is limiting, so, but 80 - 90 MB/s is possible on the specific box, the limiting factor at the moment is the bad performance of ZFS). The box is a quad core system at 3 GHz (Intel Q6600) with 8 GB of RAM running most recent FreeBSD 10.0-CURRENT/amd64. Thanks in advance, Oliver --------------enigCB2D0DE8D7C6F9A64D13F248 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iQEcBAEBAgAGBQJQthG7AAoJEOgBcD7A/5N8+5UIAOLxog/7YYzr4FSfho3AWD52 O0K1kW5suRamMsksCiS4driQEhwS7bA/emKiR/b1JSg5j6+/Kx4d32tD8CKQh/ac 7gCboQu08Mb5QrHhjN1TQFpsW/1sBUsEezErtQTFYHftBuFwGSoZbcYoZgDroFIy Vnw0Xk28FgxFflD6ZLM7NECsdGueb2AseTw369ssqsb8CuAElGvWMq7Kog88ebjK D/YBzNF1nT9ERpZ/ZdPE73VjCM9tuTglQg3o2YkgCLPhFUmW2YSy7vvBqwk9B+3d beVFp/Fr9vhx2Rdg7W56ckhjD9GhM0BsgJu8MCuuZh6mhtNTAct5S4WeZgDz5gg= =ZQzS -----END PGP SIGNATURE----- --------------enigCB2D0DE8D7C6F9A64D13F248--
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