Messages in this thread | | | From | "Martin A. Fink" <> | Subject | Re: SATA-performance: Linux vs. FreeBSD | Date | Tue, 13 Feb 2007 13:32:34 +0100 |
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Am Dienstag, 13. Februar 2007 12:25 schrieben Sie: > > Well they do. The Flash disk I have (SATA-I) is capable of 48 MB/s and this > > value is reached over the whole disk size by windows as well as by FreeBSD. > > See my test results in the first thread. > > Ok a flash disk should be more stable > > > My Seagate Barracuda Harddisk drive (SATA-II) starts with 76 MB/s and > > decreases linearly to 35 MB/s due to the fact that it has to write to a > > rotating disk. But on a flash disk there is nothing rotating... > > The hard disk one isn't guaranteed or stable but the flash especially if > it is aimed at it ought to behave. > > > So where is the difference between SATA-I and SATA-II ? > > All physical side if they are on the same controller when you do the > tests. Mostly latency, > > > And why is FreeBSD able to write with constant rates (the complete 25 GB, all > > with 48+/-0.1 MB/s) but Linux 2.6.18 not ? > > Does the FreeBSD fsync sync to media ? Also what controller is being used > here, and do you have EHCI USB support running ? Manual of FreeBSD fsync says it syncs to media.
I used the same controller: Same computer, same harddisk. two partitions on the system disk, one for linux, one for freebsd.
EHCI:
ehci_hcd 0000:00:1d.7: EHCI Host Controller ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004 usb usb1: Product: EHCI Host Controller
AHCI
ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0xf impl SATA mode
> > > With a dedicated (rotating) SATA II device, using the first 70% of disk space > > no problem -- tested ! With a SATA-I device only a problem with Linux 2.6.18 > > I suspect the SATA-1 itself may not be the decider but something else - > eg the hard disk using NCQ, which would cover up any latency related > problems. > > > Journaling of data: you are right, ext2 performs better than ext3. > > And ext3 in writeback mode ought in theory (but practice is always > harder ;)) be faster than ext2. > >
-- Dipl. Physiker Martin Anton Fink Max Planck Institute for extraterrestrial Physics Giessenbachstrasse 85741 Garching Germany Tel. +49-(0)89-30000-3645 Fax. +49-(0)89-30000-3569 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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