Date: Mon, 31 Mar 2008 11:55:42 -0700 From: Xin LI <delphij@delphij.net> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: Are large RAID stripe sizes useful with FreeBSD? Message-ID: <47F133AE.2010900@delphij.net> In-Reply-To: <fsr7fb$hl0$1@ger.gmane.org> References: <fsr7fb$hl0$1@ger.gmane.org>
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Ivan Voras wrote: > Most of new hardware RAID controllers offer stripe sizes of 128K, 256K > and some also have 512K and 1M stripes. In the simplest case of RAID0 of > two drives, knowing that the data is striped across the drives and that > FreeBSD issues IO request of at most 64K, is it useful to set stripe > sizes to anything larger than 32K? I suppose something like TCQ would > help the situation but does anyone know how is this situation usually > handled on the RAID controllers? Short answer: yes. Larger stripe sizes would allow better performance for continuous read/write. In theory they will negatively affect small size read/write but in practice you will notice that larger stripe size would give better performance in almost all cases. -- Xin LI <delphij@delphij.net> http://www.delphij.net/ FreeBSD - The Power to Serve!
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