Date: Mon, 22 Jun 2015 01:38:23 -0700 From: Xin Li <delphij@delphij.net> To: Quartz <quartz@sneakertech.com>, FreeBSD FS <freebsd-fs@freebsd.org> Subject: Re: ZFS raid write performance? Message-ID: <5587C97F.2000407@delphij.net> In-Reply-To: <5587C3FF.9070407@sneakertech.com> References: <5587C3FF.9070407@sneakertech.com>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 6/22/15 01:14, Quartz wrote: > What's sequential write performance like these days for ZFS > raidzX? Someone suggested to me that I set up a single not-raid > disk to act as a fast 'landing pad' for receiving files, then move > them to the pool later in the background. Is that actually > necessary? (Assume generic sata drives, 250mb-4gb sized files, and > transfers are across a LAN using single unbonded GigE). That sounds really weird recommendation IMHO. Did "someone" explained with the reasoning/benefit of that "landing pad"? I don't have hardware for testing handy, but IIRC even with 10,000 RPM hard drives, a single hard drive won't do much beyond 100MB/s (maybe 120MB/s max) for sequential 128kB blocks, so that "landing pad" would probably not very helpful assuming you can saturate your GigE network (and keep in mind that with a file system in place it's not a perfect sequential operation; plus if there is something wrong with that hard drive you will have to start over rather than just replacing the bad drive). Cheers, -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJVh8l+AAoJEJW2GBstM+nsD8EP/RHR8Oiqf6FFVG4LT+CSqXLc GIsSqaR/6/l04Ah0ixTkaubNvOELPlFZdFKQDtNd2u71G2Z7XtMbNvOK3G7whOxC 6a5xdNfdIYs7lq3jatN79BP9dygtgICsb1oMrCyAzd/tQc+cTvPabC/OxR4TtEJn ZumP6LworIDGp1ruMrmQ7VvcOKhCxzs4VO7G8Lcj/WkhzR3TDEsZuzzqefWg1RlO SBWJEwMGUugKWOCvgm8eQ2Hmw3btYbee1wfzuojtRN+d+IS8PtmsFpGBo8PCRSb8 lPz1Cf1fY4/zwruiG4EI+0CFvfr/05rN6DBRolyctdCGY1zX4rgKu6DT62kFkUR7 1nQdwxQ9slsQck1vyfAv2nIlGU530E696ZoS8/Ppqi/P8IqktYDLXKMn9+l0s+y+ EDzfvITasvwa6GRp5oxD2wagMjhvJ9iwELBLsppbjNH2i6n6k7EUSD1WGDHyQI2O irzm7ecRd5mym14Ruk0PxOAkuRrWhIdkSEHWrK1V5MZolIMw7MTf/gzNJPDIG0tZ MP4JmaOlysmHwIxoDLwAVlfuwweT3496miRbDvjzBrexkBvOVcIQdtymhZJmGe/z DoejzWQvub5CbsDVbNAVW6HBppbW2MEqby4zyzl/Ae/IzsvYKAdVTQdmICO7wqNz XWCqRSAjysOM5RDHoyXf =Newc -----END PGP SIGNATURE-----
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