Thanks, I'm going to try this out. I mentioned on another thread, I
wonder if this is the root cause of the contention issues reported when
recovering with OS and journals on the same SSD.
On 2013-11-25 10:11, Stefan Priebe - Profihost AG wrote:
Hi James,
after having some discussion with the kernel guys and after digging
through the kernel code and sending a patch today ;-)
It is quite easy todo this via the kernel using this one:
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=39c60a0948cc06139e2fbfe084f83cb7e7deae3b
Just do:
echo temporary write through > /sys/class/scsi_disk/<disk>/cache_type
for this disk and the kernel internally does not do any FLUSH. Even
tough the command seems to disable write back it does not.
But it still needs a patch of myself from today:
Signed-off-by: Stefan Priebe <s.priebe@xxxxxxxxxxxx>
---
drivers/scsi/sd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 734a29a..ccc6242 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -174,7 +174,7 @@ sd_store_cache_type(struct device *dev, struct
device_attribute *attr,
if (sdkp->cache_override) {
sdkp->WCE = wce;
sdkp->RCD = rcd;
- return count;
+ goto out;
}
if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer),
SD_TIMEOUT,
@@ -194,6 +194,7 @@ sd_store_cache_type(struct device *dev, struct
device_attribute *attr,
sd_print_sense_hdr(sdkp, &sshdr);
return -EINVAL;
}
+out:
revalidate_disk(sdkp->disk);
return count;
}
-- 1.7.10.4
Stefan
Am 25.11.2013 10:59, schrieb James Pearce:
Having a configurable would be ideal. User should be made beware of
the
need for super-caps via documentation in that case.
Quickly eye-balling the code... can this be patched via
journaller.cc
for testing?
_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
