|
|
|
|
From 9a106b5fbb88342f0ee02891d1bbb0e3c5a93d03 Mon Sep 17 00:00:00 2001
|
|
|
|
|
From: Donald Douwsma <ddouwsma@redhat.com>
|
|
|
|
|
Date: Fri, 15 Sep 2017 08:33:42 -0500
|
|
|
|
|
Subject: [PATCH] mkfs.xfs: Don't stagger AG for a single disk
|
|
|
|
|
|
|
|
|
|
When sunit and swidth are used mkfs.xfs tries to avoid all allocation
|
|
|
|
|
groups aligning on the same stripe and will attempt to stagger them
|
|
|
|
|
across the stripes that make up swidth. If there is only one stripe
|
|
|
|
|
then there is no benefit in this optimisation.
|
|
|
|
|
|
|
|
|
|
$ truncate -s10G xfs_10G_su256k_sw1.image
|
|
|
|
|
$ mkfs.xfs -d su=256k,sw=1 xfs_10G_su256k_sw1.image
|
|
|
|
|
meta-data=xfs_10G_su256k_sw1.image isize=512 agcount=16, agsize=163776 blks
|
|
|
|
|
= sectsz=512 attr=2, projid32bit=1
|
|
|
|
|
= crc=1 finobt=0, sparse=0
|
|
|
|
|
data = bsize=4096 blocks=2620416, imaxpct=25
|
|
|
|
|
= sunit=64 swidth=64 blks
|
|
|
|
|
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
|
|
|
|
|
log =internal log bsize=4096 blocks=2560, version=2
|
|
|
|
|
= sectsz=512 sunit=64 blks, lazy-count=1
|
|
|
|
|
realtime =none extsz=4096 blocks=0, rtextents=0
|
|
|
|
|
|
|
|
|
|
A side effect of the optimisation is that the size adjustment used to stager
|
|
|
|
|
the allocation groups causes the last sunit of storage to be unused.
|
|
|
|
|
|
|
|
|
|
$ echo $((2620416*4096))
|
|
|
|
|
10733223936
|
|
|
|
|
$ ls -l xfs_10G_su256k_sw1.image
|
|
|
|
|
-rw-rw-r--. 1 test test 10737418240 Aug 30 10:54 xfs_10G_su256k_sw1.image
|
|
|
|
|
|
|
|
|
|
Skip this optimisation when sunit == swidth.
|
|
|
|
|
|
|
|
|
|
Signed-off-by: Donald Douwsma <ddouwsma@redhat.com>
|
|
|
|
|
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
|
|
|
|
|
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
|
|
|
|
|
---
|
|
|
|
|
mkfs/xfs_mkfs.c | 4 +++-
|
|
|
|
|
1 file changed, 3 insertions(+), 1 deletion(-)
|
|
|
|
|
|
|
|
|
|
Index: xfsprogs-rhel7.5/mkfs/xfs_mkfs.c
|
|
|
|
|
===================================================================
|
|
|
|
|
--- xfsprogs-rhel7.5.orig/mkfs/xfs_mkfs.c
|
|
|
|
|
+++ xfsprogs-rhel7.5/mkfs/xfs_mkfs.c
|
|
|
|
|
@@ -2308,7 +2308,9 @@ reported by the device (%u).\n"),
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
- if (dswidth && ((agsize % dswidth) == 0) && (agcount > 1)) {
|
|
|
|
|
+ if (dswidth && ((agsize % dswidth) == 0)
|
|
|
|
|
+ && (dswidth != dsunit)
|
|
|
|
|
+ && (agcount > 1)) {
|
|
|
|
|
/* This is a non-optimal configuration because all AGs
|
|
|
|
|
* start on the same disk in the stripe. Changing
|
|
|
|
|
* the AG size by one sunit will guarantee that this
|
