Thats a simple way to collect disk attributes
    NSDictionary* fileAttributes = [[NSFileManager defaultManager] attributesOfFileSystemForPath:@"/" error:nil];
    unsigned long long freeSpace = [[fileAttributes objectForKey:NSFileSystemFreeSize] longLongValue];
    unsigned long long diskSpace = [[fileAttributes objectForKey:NSFileSystemSize] longLongValue];
    // fileAttributtes return value in bytes to convert in GB we need divide result by 1073741824
    NSLog(@"Disk Space: %dGB", (int)(diskSpace / 1073741824));
    NSLog(@"Free Space: %dGB", (int)(freeSpace / 1073741824));
We can get to many others attributes See in class reference NSFileManager