Revision 495beb42

b/man/gnt-instance.sgml
82 82
              <arg><replaceable>initrd_path</replaceable></arg>
83 83
            </group> </arg>
84 84
          <sbr>
85
          <arg>--file-storage-dir <replaceable>dir_path</replaceable></arg>
86
          <arg>--file-driver <group choice="req">
87
              <arg>loop</arg>
88
              <arg>blktap</arg>
89
            </group></arg>
90
          <sbr>
85 91
          <arg choice="req">-t<group>
86 92
              <arg>diskless</arg>
93
              <arg>file</arg>
87 94
              <arg>plain</arg>
88 95
              <arg>drbd</arg>
89 96
            </group>
......
229 236
              </listitem>
230 237
            </varlistentry>
231 238
            <varlistentry>
239
              <term>file</term>
240
              <listitem>
241
                <para>Disk devices will be regular files.</para>
242
              </listitem>
243
            </varlistentry>
244
            <varlistentry>
232 245
              <term>plain</term>
233 246
              <listitem>
234 247
                <para>Disk devices will be logical volumes.</para>
......
258 271
        </para>
259 272

  
260 273
        <para>
274
          The <option>--file-storage-dir</option> specifies the relative path
275
          under the cluster-wide file storage directory to store file-based
276
          disks. It is useful for having different subdirectories for
277
          different instances. The full path of the directory where the disk
278
          files are stored will consist of cluster-wide file storage directory
279
          + optional subdirectory + instance name. Example:
280
          /srv/ganeti/file-storage/mysubdir/instance1.example.com. This option
281
          is only relevant for instances using the file storage backend.
282
        </para>
283

  
284
        <para>
285
          The <option>--file-driver</option> specifies the driver to use for
286
          file-based disks. Note that currently these drivers work with the
287
          xen hypervisor only. This option is only relevant for instances using
288
          the file storage backend. The available choices are:
289
          <variablelist>
290
            <varlistentry>
291
              <term>loop</term>
292
              <listitem>
293
                <para>Kernel loopback driver.</para>
294
              </listitem>
295
            </varlistentry>
296
            <varlistentry>
297
              <term>blktap</term>
298
              <listitem>
299
                <para>blktap driver.</para>
300
              </listitem>
301
            </varlistentry>
302
          <variablelist>
303
        </para>
304

  
305
        <para>
306
          The loop driver uses loopback devices to access the filesystem
307
          within the file. However, running I/O intensive applications
308
          in your instance using the loop driver might result in slowdowns.
309
          Furthermore, if you use the loopback driver consider increasing
310
          the maximum amount of loopback devices (on most systems it's 8)
311
          using the max_loop param.
312
        </para>
313

  
314
        <para>
315
          In order to be able to use the blktap driver you should check
316
          if the 'blktapctrl' user space disk agent is running (usually
317
          automatically started via xend). This user-level disk I/O
318
          interface has the advantage of better performance. Especially
319
          if you use a network file system (e.g. NFS) to store your instances
320
          this is the recommended choice.
321
        </para> 
322

  
323
        <para>
261 324
          Example:
262 325
          <screen>
326
# gnt-instance add -t file -s 30g -m 512 -o debian-etch \
327
  -n node1.example.com --file-storage-dir=mysubdir instance1.example.com
263 328
# gnt-instance add -t plain -s 30g -m 512 -o debian-etch \
264 329
  -n node1.example.com instance1.example.com
265 330
# gnt-instance add -t drbd -s 30g -m 512 -o debian-etch \

Also available in: Unified diff