Hi:
Thanks Nathan. I wanted to use ramdisk only to store filenames, and the
actual data in realtime subvolume. Thoguht it'll have better performance.
However I've now repartioned my disk to have two partitions: one of
100GB and the other of 800GB (/dev/sda1 and /dev/sda2 respectively). I'm using
/dev/sda1 as my regular xfs volume (log plus metadata), and configured /dev/sda2
as the realtime subvolume. This is the output of mkfs.xfs:
dop93:~ # mkfs -t xfs -f -d unwritten=0 -r rtdev=/dev/sda2 /dev/sda1
meta-data=/dev/sda1 isize=256 agcount=25, agsize=1048576 blks
= sectsz=512
data = bsize=4096 blocks=25601577, imaxpct=25
= sunit=0 swidth=0 blks, unwritten=0
naming =version 2 bsize=4096
log =internal log bsize=4096 blocks=12500, version=1
= sectsz=512 sunit=0 blks
realtime =/dev/sda2 extsz=65536 blocks=208836967,
rtextents=13052310
dop93:~ # mount -t xfs -o rtdev=/dev/sda2 /dev/sda1 /mnt
It's been good so far. Now how do I determine the amount of free space
in my realtime subvolume? Do I need to have the realtime subvolume on another
device altogether (instead of another partition) to get better performance?
I don't know what version of XFS I'm using (it's not v1.3, but the one
packaged with SuSE 8.1). I have new version ( 2.2.1-28) of xfsprogs though.
In the mean time I also tried to write a 'realtime' file on the realtime
subvolume - but SuSE 8.1 seems to have disabled O_DIRECT and O_LARGEFILE
support. Any clues on that? I'm trying hard to get the realtime subvolumes
working - hopefully it is more deterministic than the regular buffered I/O. Any
info on these lines would be great. Thanks in advance.
-Ramesh
> On Thu, Feb 12, 2004 at 03:55:10PM +0000, Ramesh K wrote:
> >
> > Hello,
> > I'm trying to use realtime subvolumes under Linux (SuSE 8.1, running
> > kernel 2.4.19-64GB-SMP (I know it is very old!!)
>
> You should be aware that realtime support is marked experimental
> and may not function correctly. That said, Eric made several
> fixes in this area awhile ago and the last time I tested it, it
> was looking much more stable.
>
> > The hardware: I'm using a 3ware RAID controller, and am using RAID level
> > 0 (all eight 120GByte disks together are seen as one disk of 960 GByte
> > device).
> > Now I want to use this entire 960 GBytes for my realtime data, and want
> > to place metadata on ramdisk. When I try:
> > dop93:> mkfs -t xfs -f -d unwritten=0 -r rtdev=/dev/sda1 /dev/ram1,
> >
> > I get warnings on block size of ramdisk. And when I try to mount the
>
> What is the warning?
>
> > device with: mount -t xfs -o rtdev /dev/sda1 - the call never returns.
> > Am I doing something very gross? Thanks.
>
> That mount line is incorrect, you need to use something like:
> mount -t xfs -o rtdev=/dev/sda1 /dev/ram1 /mnt
>
> It seems odd to be using a ram disk in this way...
>
> cheers.
>
> --
> Nathan
>
**************************************************************************
Ramesh K
(Mo/Tu): Radiosterrenwacht Westerbork, Schattenburg 1, 9433 TA Zwiggelte.
ph: +31-(0)593-598755 fax:+31-(0)593-592486
(We/Th/Fr): Stitching Astron, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo.
ph: +31-(0)521-595255 fax:+31-(0)521-597332
**************************************************************************
|