Date: Sun, 20 Jun 2010 12:09:25 -0700 From: Artem Belevich <fbsdlist@src.cx> To: oizs <oizs@freemail.hu> Cc: freebsd-current@freebsd.org Subject: Re: Dell Perc 5/i Performance issues Message-ID: <AANLkTinYsUMVdlFNYnw4RFMPWdWqhzFUlQYIznNTq2PP@mail.gmail.com> In-Reply-To: <4C1E4722.3050506@freemail.hu> References: <4C1AB4C0.4020604@freemail.hu> <A594C946-32C0-4C4A-AA37-0E81D270162A@mac.com> <4C1B3792.9000007@freemail.hu> <AANLkTimsHZLREByndqXEjt2yjdvOYVV7Rnw8AMjqxYIl@mail.gmail.com> <4C1C0ED9.8090103@freemail.hu> <2F904ED8-BC95-459F-8536-A889ADDA8D31@samsco.org> <4C1E4722.3050506@freemail.hu>
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/dev/random and /dev/urandom are relatively slow and are not suitable as the source of data for testing modern hard drives' sequential throughput. On my 3GHz dual-core amd63 box both /dev/random and /dev/urandom max out at ~80MB/s while consuming 100% CPU time on one of the processor cores. That would not be enough to saturate single disk with sequential writes. --Artem On Sun, Jun 20, 2010 at 9:51 AM, oizs <oizs@freemail.hu> wrote: > I've tried almost everything now. > The battery is probably fine: > mfiutil show battery > mfi0: Battery State: > =A0Manufacture Date: 7/25/2009 > =A0 =A0Serial Number: 3716 > =A0 =A0 Manufacturer: SMP-PA1.9 > =A0 =A0 =A0 =A0 =A0 =A0Model: DLFR463 > =A0 =A0 =A0 =A0Chemistry: LION > =A0Design Capacity: 1800 mAh > =A0 Design Voltage: 3700 mV > =A0 Current Charge: 99% > > My results: > Settings: > Raid5: > Stripe: 64k > mfiutil cache 0 > mfi0 volume mfid0 cache settings: > =A0 =A0 =A0I/O caching: writes > =A0 =A0write caching: write-back > =A0 =A0 =A0 read ahead: none > drive write cache: default > Raid0: > Stripe: 64k > mfiutil cache 0 > mfi0 volume mfid0 cache settings: > =A0 =A0 =A0I/O caching: writes > =A0 =A0write caching: write-back > =A0 =A0 =A0 read ahead: none > drive write cache: default > > Tried to play around with this as well, with almost no difference. > > Raid5 > read: > dd if=3D/dev/mfid0 of=3D/dev/null bs=3D10M > 1143+0 records in > 1143+0 records out > 11985223680 bytes transferred in 139.104134 secs (86160083 bytes/sec) > write: > dd if=3D/dev/random of=3D/dev/mfid0 bs=3D64K > 22747+0 records in > 22747+0 records out > 1490747392 bytes transferred in 23.921103 secs (62319342 bytes/sec) > > Raid0 > read: > dd if=3D/dev/mfid0 of=3D/dev/null bs=3D64K > 92470+0 records in > 92470+0 records out > 6060113920 bytes transferred in 47.926007 secs (126447294 bytes/sec) > write: > dd if=3D/dev/random of=3D/dev/mfid0 bs=3D64K > 16441+0 records in > 16441+0 records out > 1077477376 bytes transferred in 17.232486 secs (62525939 bytes/sec) > > I'm writing directly to the device so im not sure any slice issues could > cause the problems. > > -zsozso > On 2010.06.20. 4:53, Scott Long wrote: >> >> Two big things =A0can affect RAID-5 performance: >> >> 1. Battery backup. =A0If you don't have a working battery attached to th= e >> card, it will turn off the write-back cache, no matter what you do. =A0C= heck >> this. =A0If you're unsure, use the mfiutil tool that I added to FreeBSD = a few >> months ago and send me the output. >> >> 2. Partition alignment. =A0If you're using classic MBR slices, everythin= g >> gets misaligned by 63 sectors, making it impossible for the controller t= o >> optimize both reads and writes. =A0If the array is used for secondary st= orage, >> simply don't use an MBR scheme. =A0If it's used for primary storage, try= using >> GPT instead and setting up your partitions so that they are aligned to l= arge >> power-of-2 boundaries. >> >> Scott >> >> On Jun 18, 2010, at 6:27 PM, oizs wrote >> > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org= " >
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