Date: Tue, 19 Aug 2003 13:42:06 +0900 From: Hidetoshi Shimokawa <simokawa@sat.t.u-tokyo.ac.jp> To: <kyriazis@meer.net> Cc: freebsd-firewire@freebsd.org Subject: Re: firewire disk spindown and other questions Message-ID: <ybs8ypqjm1t.wl@ett.sat.t.u-tokyo.ac.jp> In-Reply-To: <54827.209.157.141.26.1060837094.squirrel@webmail.meer.net> References: <54827.209.157.141.26.1060837094.squirrel@webmail.meer.net>
next in thread | previous in thread | raw e-mail | index | archive | help
At Wed, 13 Aug 2003 21:58:14 -0700 (PDT), <kyriazis@meer.net> wrote: > > Hello freebsd-firewire. > > I am new to freebsd, and I am planning on changing my file > server from linux to freebsd. > > At the same time I would also like to move to firewire > (from ide). I don't have large bandwidth requirements, so I'm > just assuming that I'm not going to get too much lower performance. > > One basic question that I have is: Is it possible to set an > automatic spindown of my firewire drives? I looked at the camcontrol > manpage, but it doesn't say anything interesting. freebsd-scsi should be the better place to ask this question. There might be a mode page to control the automatic spindown but I don't know. > I am planning on setting up a raid-5 array (on firewire). Are there > any issues that I should be aware of?? Since I haven't tried > firewire yet, and I am (slightly) worried about performance, I wonder > if putting all drives on one chain will give me problems. Would > splitting drives over multiple firewire busses on the same card help > any, or would I have to get multiple firewire cards to increase > performance? Note, this is a server machine, so I'll only be accessing > data through 100Mbit ethernet via samba. Because ports share the bandwidth of the bus, you need another card(chip) to increase bandwidth. You can have only a bus by a chip even if it has multiple ports. I got about 32MB/s for a drive and 40 MB/s for two drives on a same bus under sequential read. Also, you could notice performance decreasing for buses which have large number of nodes because of arbitration gap count increasing. > Also, I was wondering if there are problems with the order firewire > clients are brought up in the bus. Will they come up as different > each time I boot up? Ie, if I have 2 disks, coming up as da0 and da1, > will the same disk come up as da0? Or will I have cases where one > disk will come up as da0, then after a reboot the other disk will come > up as ad0? If that is in fact the case, will that cause problem with > vinum identifying which disk is which, or will it work because of the > labels vinum puts on the disks themselves? If you plan to use FreeBSD-5.X, geom_vol_ffs kernel module would help. It wires down the specific UFS partition to specific device name. If you don't mind to apply a patch to sbp.c, you can hard-code EUI64->target id mapping table into the source code. The biggest problem for wire-down in SBP is that SBP has (64+48)bit identifier for the device but CAM cannot handle such big number. So we have to map the device to small target numbers sequentially. > Thank you!! > > --george /\ Hidetoshi Shimokawa \/ simokawa@sat.t.u-tokyo.ac.jp PGP public key: http://www.sat.t.u-tokyo.ac.jp/~simokawa/pgp.html
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?ybs8ypqjm1t.wl>