做過kickstart或者cobbler的同學應該都知道,在系統安裝結束後可以對系統作一些定製化的配置,比如ip,分區,硬盤,包等。
下面講講我在寫%post時遇到的一些關於硬盤分區的問題。
廢話不多說,先貼上處理硬盤的腳本,這裏只是處理非系統盤的其他硬盤。
echo "Dealing with data disks now..."
NUM=01
DATA_DISK=""
for DEVICE in `awk '$NF ~ /sd/ && $NF !~ /[0-9]$/ {print $NF}' /proc/partitions | sort`; do
DEVICE="/dev/$DEVICE"
FSTYPE=""
LABEL=""
FSTYPE=`parted -s ${DEVICE}1 print 2>&1 | awk '/^ / {print $5}'`
LABEL=`e2label ${DEVICE}1 2>/dev/null`
NEW_LABEL="/hadoop$NUM"
# Skip swap partition, which wouldn't have a label
echo $FSTYPE | grep swap > /dev/null
if [ $? -eq 0 ]; then
echo "Partition ${DEVICE}1 is a SWAP, skipping..."
continue
fi
# Skip "/" LABEL
if [ "$LABEL" = "/" ]; then
echo "Device ${DEVICE}1 has label '/', skipping..."
continue
fi
# Skip label "/var/log/hadoop"
if [ "$LABEL" = "/var/log/hadoop" ]; then
echo "Device ${DEVICE}1 has label /var/log/hadoop, skipping..."
continue
fi
# If LABEL is null , create partition ,then label and filesystem
if [ -z "$LABEL" ]; then
FSTYPE=ext4
echo "Creating gpt "
parted -s $DEVICE mklabel gpt
echo "Creating new partition on $DEVICE with label $NEW_LABEL..."
parted -s $DEVICE mkpart primary $FSTYPE 0% 100% 2>&1
echo "Formatting filesystem ${DEVICE}1..."
partprobe
sleep 3
mkfs.$FSTYPE -q -N 61050880 -L $NEW_LABEL -m 1 -O sparse_super ${DEVICE}1 2>&1 &
# If LABEL is not null , rewrite label
else
echo "Rewrite Label of ${DEVICE}1 to $NEW_LABEL"
e2label ${DEVICE}1 $NEW_LABEL
fi
echo "Adding entry for $NEW_LABEL into /etc/fstab..."
grep -w "LABEL=$NEW_LABEL $NEW_LABEL" /etc/fstab > /dev/null
if [ $? -eq 0 ]; then
perl -pi -e "s|LABEL=$NEW_LABEL $NEW_LABEL .*$|LABEL=$NEW_LABEL $NEW_LABEL $FSTYPE defaults,noatime,nodiratime 0 0|" /etc/fstab 2>&1
else
echo "LABEL=$NEW_LABEL $NEW_LABEL $FSTYPE defaults,noatime,nodiratime 0 0" >> /etc/fstab
fi
# Create a mount point
if [ ! -d $NEW_LABEL ]; then
echo "Creating mount point $NEW_LABEL ..."
mkdir -p $NEW_LABEL
fi
# Increase NUM by 1
NUM=`expr $NUM + 1 | awk '{printf("%02s",$1)}'`
# Put all partitions of data disks into string list
DATA_DISK="$DATA_DISK ${DEVICE}1"
done
echo "Waiting for all mkfs processes to finish (if any)..."
wait
if [ -n "$DATA_DISK" ]; then
echo "Tuning newly formatted filesystems..."
FS=""
for FS in $DATA_DISK; do
tune2fs -i 0 -c 0 $FS 2>&1
done
fi
echo "mount all disks now"
mount -a
解釋1:
parted -s $DEVICE mkpart primary $FSTYPE 0% 100% 2>&1
代表在DEVICE上創建分區,分區的跨度是從0%開始到100%結束,單位默認是MB,也可以用其他寫法,比如百分比的方式:
parted -s $DEVICE mkpart primary $FSTYPE 0 200000 2>&1
或者採用扇區的方式,如下命令表示起始扇區是34sectors
parted -s $DEVICE mkpart primary $FSTYPE 34s 100% 2>&1
解釋2:
上面腳本中有partprobe這個命令,它是用來告訴kernel重新讀取硬盤的扇區信息。
如果不加這條命令,在安裝完系統後你會發現有些硬盤沒有被正確格式化,也就是mkfs命令沒有正確執行。
相關報錯信息如下:
Could not stat/dev/sdi1 --- No such file or directory
The deviceapparently does not exist; did you specify it correctly?
你想知道怎麼看到日誌信息的?
請在你的postinstall腳本中把日誌都打到一個文件中。
以上報錯信息不總是出現,只是有時會出現,原因就是因爲在劃分好扇區後,kernel沒有及時讀取對應硬盤的扇區信息,所以在格式化硬盤的時候就找不到對應的扇區,跑一下partprobe來告訴kernel再重新讀取下硬盤扇區信息,這樣就不會出現上面的報錯信息了。
解釋3:
通常你會在日誌中看到如下信息
Warning: The resulting partition is not properly aligned for best performance.
你不用擔心硬盤性能會受到影響,大部分硬盤的logical size 和physical size都是512B,有些硬盤的physical size是4KB,對於這種硬盤就需要在劃分分區的時候注意下,分區起始要是1MB,parted工具會幫你處理這些的,所以不用擔心,不放心的話,可以用下面介紹的命令查看下分區情況。
附,硬盤操作相關的一些命令
顯示硬盤/dev/sdb的分區情況
parted /dev/sdb print free 2>&1
parted /dev/sdb unit mb print free 2>&1
刪除分區/dev/sdb1
parted /dev/sdb rm 1
創建gpt表
parted -s /dev/sdb mklabel gpt
格式化分區/dev/sdb1
mkfs.ext4 -q -N 61050880 -L /hadoop01 -m 1 -O sparse_super /dev/sdb1 2>&1
IO-limit相關的文章鏈接
http://people.redhat.com/msnitzer/docs/io-limits.txt