Set 32k csum_block_size for HDD by default

src/disk_tool.cpp

@@ -60,7 +60,7 @@ static const char *help_text =
     "    --block_size 128k/1M       Set blockstore object size\n"
     "    --bitmap_granularity 4k    Set bitmap granularity\n"
     "    --data_csum_type none      Set data checksum type (crc32c or none)\n"
-    "    --csum_block_size 4k       Set data checksum block size\n"
+    "    --csum_block_size 4k/32k   Set data checksum block size (SSD/HDD default)\n"
     "    --data_device_block 4k     Override data device block size\n"
     "    --meta_device_block 4k     Override metadata device block size\n"
     "    --journal_device_block 4k  Override journal device block size\n"

src/disk_tool_prepare.cpp

@@ -111,6 +111,8 @@ int disk_tool_t::prepare_one(std::map<std::string, std::string> options, int is_
             options["block_size"] = "1M";
         if (is_hybrid && options["throttle_small_writes"] == "")
             options["throttle_small_writes"] = "1";
+        if (!is_hybrid && options.find("data_csum_type") != options.end() && options.at("data_csum_type") != "")
+            options["csum_block_size"] = "32k";
     }
     else if (!json_is_true(options["disable_data_fsync"]))
     {