/dev/sda6 97% Usage - cannot update passive node

Hello Gentlemen,

After unsuccessful update I had to reinstall a failed node from an ISO and than update it manually. Once I got this node as up-to-date I have tried to update passive node.
But it failed with error: Up2Date failed: Not enough free space for '/var/up2date/sys-install'. Required space: 362738 KB Available space: 168524 KB; inodes: 306307

On the master node /dev/sda6 - show 1.5Gb of free space:
<M> utm:/ # df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda6       5.2G  3.5G  1.5G  71% /
udev            3.9G  116K  3.9G   1% /dev
tmpfs           3.9G     0  3.9G   0% /dev/shm
/dev/sda1       331M   16M  295M   5% /boot
/dev/sda5       113G  4.9G  102G   5% /var/storage
/dev/sda7       148G   18G  123G  13% /var/log
/dev/sda8       6.0G  245M  5.5G   5% /tmp
tmpfs           3.9G     0  3.9G   0% /var/sec/chroot-httpd/dev/shm
tmpfs           3.9G     0  3.9G   0% /var/storage/chroot-reverseproxy/dev/shm
tmpfs           3.9G  100K  3.9G   1% /var/storage/chroot-smtp/tmp/ram
tmpfs           3.9G  226M  3.7G   6% /var/storage/chroot-http/tmp
<M> utm:/ #


But on the Slave node 165Mb only:
<S> utm:/ # df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda6       5.2G  4.8G  165M  97% /
udev            3.9G  104K  3.9G   1% /dev
tmpfs           3.9G     0  3.9G   0% /dev/shm
/dev/sda1       331M   16M  295M   5% /boot
/dev/sda5       115G  5.5G  103G   6% /var/storage
/dev/sda7       150G   25G  118G  18% /var/log
/dev/sda8       6.1G  243M  5.5G   5% /tmp
tmpfs           3.9G     0  3.9G   0% /var/sec/chroot-httpd/dev/shm
tmpfs           3.9G     0  3.9G   0% /var/storage/chroot-reverseproxy/dev/shm
tmpfs           3.9G  4.0K  3.9G   1% /var/storage/chroot-smtp/tmp/ram
tmpfs           3.9G  225M  3.7G   6% /var/storage/chroot-http/tmp
<S> utm:/ #


Is it a cause why I cannot update the slave node?

How I can find and delete old garbage from /sda6?

Thanks
Sergio