After fix for ZBX-3269, Zabbix become to able to monitor partitions.
But the definition of "MAX_DISKDEVICES" in src/zabbix_agent/diskdevices.h is still 8.
So, Zabbix cannot monitor more than 8 disks or partitions.

I think the environment having more than 8 partitions is not rare.
I suggest to change "MAX_DISKDEVICES" to bigger number, like 64 or 128.

How to reproduce:
If we have following device files.
sda,sda1,sda2,sda3,sda4,sdb,sdb1,sdb2,sdb3,sdb4
Add devices.
zabbix_get -s localhost -k vfs.dev.write[sda]
zabbix_get -s localhost -k vfs.dev.write[sda1]
zabbix_get -s localhost -k vfs.dev.write[sda2]
zabbix_get -s localhost -k vfs.dev.write[sda3]
zabbix_get -s localhost -k vfs.dev.write[sda4]
zabbix_get -s localhost -k vfs.dev.write[sdb]
zabbix_get -s localhost -k vfs.dev.write[sdb1]
zabbix_get s localhost -k vfs.dev.write[sdb2] <--- this returns "ZBX_NOTSUPPORTED"
zabbix_get s localhost -k vfs.dev.write[sdb3] <--- this returns "ZBX_NOTSUPPORTED"
zabbix_get s localhost -k vfs.dev.write[sdb4] <--- this returns "ZBX_NOTSUPPORTED"

• Implicitly "all" disk device statistics is collected and it consume one ZBX_SINGLE_DISKDEVICE_DATA.
  So, the above test returns "ZBX_NOTSUPPORTED" at 8th device.