vitastor/mon/simple-offsets.js

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// Copyright (c) Vitaliy Filippov, 2019+
// License: MIT
// Simple tool to calculate journal and metadata offsets for a single device
// Will be replaced by smarter tools in the future
const fs = require('fs').promises;
const child_process = require('child_process');
async function run()
{
const options = {
object_size: 128*1024,
bitmap_granularity: 4096,
journal_size: 16*1024*1024,
device_block_size: 4096,
journal_offset: 0,
device_size: 0,
format: 'text',
};
for (let i = 2; i < process.argv.length; i++)
{
if (process.argv[i].substr(0, 2) == '--')
{
options[process.argv[i].substr(2)] = process.argv[i+1];
i++;
}
}
if (!options.device)
{
process.stderr.write('USAGE: nodejs '+process.argv[1]+' --device /dev/sdXXX\n');
process.exit(1);
}
options.device_size = Number(options.device_size);
let device_size = options.device_size;
if (!device_size)
{
const st = await fs.stat(options.device);
options.device_block_size = st.blksize;
if (st.isBlockDevice())
device_size = Number(await system("/sbin/blockdev --getsize64 "+options.device))
else
device_size = st.size;
}
if (!device_size)
{
process.stderr.write('Failed to get device size\n');
process.exit(1);
}
options.journal_offset = Math.ceil(options.journal_offset/options.device_block_size)*options.device_block_size;
const meta_offset = options.journal_offset + Math.ceil(options.journal_size/options.device_block_size)*options.device_block_size;
const entries_per_block = Math.floor(options.device_block_size / (24 + 2*options.object_size/options.bitmap_granularity/8));
const object_count = Math.floor((device_size-meta_offset)/options.object_size);
const meta_size = Math.ceil(object_count / entries_per_block) * options.device_block_size;
const data_offset = meta_offset + meta_size;
const meta_size_fmt = (meta_size > 1024*1024*1024 ? Math.round(meta_size/1024/1024/1024*100)/100+" GB"
: Math.round(meta_size/1024/1024*100)/100+" MB");
if (options.format == 'text' || options.format == 'options')
{
if (options.format == 'text')
{
process.stderr.write(
`Metadata size: ${meta_size_fmt}\n`+
`Options for the OSD:\n`
);
}
process.stdout.write(
` --data_device ${options.device}\n`+
` --journal_offset ${options.journal_offset}\n`+
` --meta_offset ${meta_offset}\n`+
` --data_offset ${data_offset}\n`+
(options.device_size ? ` --data_size ${device_size-data_offset}\n` : '')
);
}
else if (options.format == 'env')
{
process.stdout.write(
`journal_offset=${options.journal_offset}\n`+
`meta_offset=${meta_offset}\n`+
`data_offset=${data_offset}\n`+
`data_size=${device_size-data_offset}\n`
);
}
else
process.stdout.write('Unknown format: '+options.format);
}
function system(cmd)
{
return new Promise((ok, no) => child_process.exec(cmd, { maxBuffer: 64*1024*1024 }, (err, stdout, stderr) => (err ? no(err.message) : ok(stdout))));
}
run().catch(err => { console.error(err); process.exit(1); });