Disk not showing the correct available space

We are using aerospike on redhat linux azure vm. After installing aerospike, the moment we do “df -h” we are getting this output : /dev/sdc 64Z 64Z 252G 100% /. Why am i getting this ? This is the aerospike namespace configuration.

namespace ns_ssd
replication-factor 2 memory-size 20G default-ttl 30d # 30 days, use 0 to never expire/evict.

storage-engine device {     # Configure the storage-engine to use persistence
            device /dev/sdc    # raw device. Maximum size is 2 TiB
            write-block-size 128K   # adjust block size to make it efficient for SSDs.
            read-page-cache true
    }

linux version : “CentOS Linux release 7.7.1908 (Core)”

You are configured to use raw device, this means Aerospike will bypass the filesystem and write directly to the device. Since we are writing to the device in this method, df cannot know how much space is used. Aerospike does have namespace metrics to indicate disk usage.

@kporter if writing directly to raw device, there shouldn’t be a filesystem left to report - right? I was under the impression df only printed formatted filesystems for linux like xfs/ext4. Wondering if Atif wiped his rootvol or something, or maybe just didnt wipe the drive first?

Right, I guess this probably means that the @Atif_Iqbal has created a mount for this device.

@Atif_Iqbal when you configure Aerospike to use a raw device, we will overwrite the existing filesystem (if one exists). This means there really shouldn’t be any filesystem mounts to the devices.