[HD2 Android NAND Development] john0902:
Thanks, that's exactly what I needed. After backing up, resizing paritions, and restoring, I deleted the script, deleted the symbolic link, deleted the /sd-ext/dalvik-cache, and rebooted. The dalvik cache is back to internal memory.

I resized the partitions to 297mb for system and 614mb for data. It looks like this:

/dev/block/mtdblock3 297.0M 290.0M 7.0M 98% /system
/dev/block/mtdblock5 614.9M 515.5M 99.4M 84% /data
/dev/block/mtdblock4 10.0M 1.1M 8.9M 11% /mnt/cache
/dev/block/mmcblk0p2 1.8G 582.8M 1.1G 34% /sd-ext

The (internal memory) data partition holds the dalvik-cache and app data:

#du -chd 1 /data/ |grep -v K
257.2M	/data/dalvik-cache
2.5M	/data/system
236.0M	/data/data
496.0M	total

I aimed for ~100mb free space on data. I figured Android needed this extra because I used to get 'low space' warnings before using A2SD when data got below ~100mb.

The (linked to sd-ext) external memory parts of the data partition hold only essentially the user apps:

550.0M	/sd-ext/app
669.0K	/sd-ext/app-private
550.6M	/sd-ext/
550.6M	total

The internal system partition has room for the ~150mb contents of system ROM, plus room for ~150mb of user apps to be migrated off external memory by conversion to system apps.

In case it helps others, here's the list of apps I successfully converted to system apps and their sizes:

-rw-r--r-- 1 root root 4657807 Jan 18 21:49 au.com.shiftyjelly.pocketcasts.apk
-rw-r--r-- 1 root root 132195 Jan 18 18:21 aws.apps.networkInfoIi.apk
-rw-r--r-- 1 root root 84453 Jan 15 22:15 bazaar.android.apk
-rw-r--r-- 1 root root 332826 Jan 18 10:17 com.a0soft.gphone.aTrackDog.apk
-rw-r--r-- 1 root root 1957845 Jan 18 20:29 com.abcOrganizer.apk
-rw-r--r-- 1 root root 1822486 Jan 15 22:39 com.akimbo.abp.apk
-rw-r--r-- 1 root root 4917000 Jan 31 16:18 com.alphonso.pulse.apk
-rw-r--r-- 1 root root 3759786 Jan 15 20:49 com.amazon.venezia.apk
-rw-r--r-- 1 root root 1734674 Jan 17 17:31 com.azumio.instantheartrate.full.apk
-rw-r--r-- 1 root root 4164741 Jan 15 20:46 com.box.android.apk
-rw-r--r-- 1 root root 2061521 Jan 15 22:04 com.calengoo.android.apk
-rw-r--r-- 1 root root 709482 Jan 31 16:22 com.cyo.comicrack.viewer.free.apk
-rw-r--r-- 1 root root 1915987 Jan 15 20:29 com.dictionary.paid.apk
-rw-r--r-- 1 root root 1468773 Jan 17 15:45 com.dooblou.SECuRETLiveStream.apk
-rw-r--r-- 1 root root 3161892 Jan 15 20:38 com.dropbox.android.apk
-rw-r--r-- 1 root root 1761105 Jan 26 22:25 com.dynamixsoftware.printershare.amazon.apk
-rw-r--r-- 1 root root 3344018 Jan 17 16:11 com.endomondo.android.pro.apk
-rw-r--r-- 1 root root 6928607 Feb 1 22:40 com.evernote.apk
-rw-r--r-- 1 root root 2583428 Jan 15 20:02 com.extendedcontrols.apk
-rw-r--r-- 1 root root 4023889 Jan 15 21:07 com.facebook.katana.apk
-rw-r--r-- 1 root root 2795884 Jan 15 21:08 com.facebook.orca.apk
-rw-r--r-- 1 root root 546903 Jan 31 16:16 com.farproc.wifi.analyzer.apk
-rw-r--r-- 1 root root 36004 Jan 15 22:35 com.farproc.wifi.connecter.apk
-rw-r--r-- 1 root root 63601 Jan 18 18:22 com.flopcode.android.networkbrowser.apk
-rw-r--r-- 1 root root 1931256 Jan 26 22:19 com.funkyfresh.samba.apk
-rw-r--r-- 1 root root 4646396 Jan 31 16:20 com.gau.go.launcherex.apk
-rw-r--r-- 1 root root 3969132 Jan 17 17:35 com.gau.go.launcherex.theme.ommd.apk
-rw-r--r-- 1 root root 352156 Jan 17 17:33 com.gau.golauncherex.notification.apk
-rw-r--r-- 1 root root 188678 Feb 1 22:43 com.google.android.apps.chrometophone.apk
-rw-r--r-- 1 root root 4408080 Jan 15 19:58 com.google.android.apps.googlevoice.apk
-rw-r--r-- 1 root root 5759085 Jan 26 22:28 com.google.android.apps.maps.apk
-rw-r--r-- 1 root root 8735073 Jan 17 15:03 com.google.android.apps.plus.apk
-rw-r--r-- 1 root root 3206269 Jan 17 15:15 com.google.android.apps.shopper.apk
-rw-r--r-- 1 root root 147351 Jan 15 21:53 com.google.android.diskusage.apk
-rw-r--r-- 1 root root 2248607 Jan 15 00:37 com.google.android.gm.apk
-rw-r--r-- 1 root root 288315 Jan 17 05:51 com.google.android.street.apk
-rw-r--r-- 1 root root 2321797 Jan 15 20:57 com.google.android.voicesearch.apk
-rw-r--r-- 1 root root 2234891 Jan 15 21:27 com.google.android.youtube.apk
-rw-r--r-- 1 root root 603626 Jan 15 21:39 com.google.zxing.client.android.apk
-rw-r--r-- 1 root root 317067 Jan 18 18:12 com.googlecode.droidwall.apk
-rw-r--r-- 1 root root 2457853 Jan 24 17:39 com.handyapps.tasksntodos10.apk
-rw-r--r-- 1 root root 1482052 Jan 15 20:38 com.ideashower.readitlater.pro.apk
-rw-r--r-- 1 root root 32465 Jan 17 17:36 com.idunnolol.headsetblocker.apk
-rw-r--r-- 1 root root 148725 Jan 15 20:34 com.jarodyv.livewallpaper.plasmatree.apk
-rw-r--r-- 1 root root 292439 Jan 17 17:30 com.leinardi.kitchentimer.apk
-rw-r--r-- 1 root root 3856373 Jan 15 19:24 com.levelup.beautifulwidgets.apk
-rw-r--r-- 1 root root 2413181 Jan 15 19:25 com.levelup.bw.forecast.apk
-rw-r--r-- 1 root root 75934 Jan 15 22:16 com.lexa.fakegpsdonate.apk
-rw-r--r-- 1 root root 109451 Jan 29 19:50 com.manor.currentwidget-1.apk
-rw-r--r-- 1 root root 611298 Jan 31 16:19 com.mendhak.gpslogger.apk
-rw-r--r-- 1 root root 63668 Jan 15 22:28 com.meowsbox.btgps.apk
-rw-r--r-- 1 root root 2538625 Jan 15 20:44 com.mobitobi.android.gentlealarm.apk
-rw-r--r-- 1 root root 16871 Jan 15 20:44 com.mobitobi.android.gentlealarmwidget.apk
-rw-r--r-- 1 root root 172349 Jan 15 20:35 com.nlucas.popupnotifications.apk
-rw-r--r-- 1 root root 1857959 Jan 15 21:55 com.okcupid.okcupid.apk
-rw-r--r-- 1 root root 1760053 Jan 17 03:55 com.pandora.android.apk
-rw-r--r-- 1 root root 986602 Jan 20 19:14 com.qs.enhancedemail.apk
-rw-r--r-- 1 root root 207030 Jan 15 21:53 com.raue.freeappnotifier.apk
-rw-r--r-- 1 root root 1814398 Jan 25 07:34 com.rdr.widgets.core.apk
-rw-r--r-- 1 root root 450049 Jan 15 20:35 com.sebastian.statsdonate.apk
-rw-r--r-- 1 root root 1495029 Jan 15 22:40 com.snoggdoggler.android.applications.doggcatcher.v1_0.apk
-rw-r--r-- 1 root root 279097 Jan 18 02:28 com.speedsoftware.rootexplorer.apk
-rw-r--r-- 1 root root 670450 Jan 15 20:41 com.teslacoilsw.quicksshd.apk
-rw-r--r-- 1 root root 1513746 Jan 18 17:54 com.tinjasoft.tasks.apk
-rw-r--r-- 1 root root 1260848 Jan 15 21:58 com.tmobile.selfhelp.apk
-rw-r--r-- 1 root root 5031807 Jan 15 19:35 com.touchtype.swiftkey.apk
-rw-r--r-- 1 root root 3875609 Jan 17 16:09 com.trimble.outdoors.gpsapp.android.apk
-rw-r--r-- 1 root root 202574 Jan 16 22:10 com.xinlu.gvdial.apk
-rw-r--r-- 1 root root 1231312 Jan 15 20:48 com.zegoggles.smssync.apk
-rw-r--r-- 1 root root 666193 Jan 15 20:17 de.dbware.circlelauncher.apk
-rw-r--r-- 1 root root 1222978 Jan 15 20:27 de.leihwelt.android.daysleftpro.apk
-rw-r--r-- 1 root root 111679 Jan 15 22:25 googoo.android.btgps.apk
-rw-r--r-- 1 root root 262716 Jan 18 18:22 info.lamatricexiste.network.apk
-rw-r--r-- 1 root root 1978295 Jan 15 22:28 it.medieval.blueftp.apk
-rw-r--r-- 1 root root 4298069 Jan 26 22:54 kov.theme.ics-2.apk
-rw-r--r-- 1 root root 846883 Jan 15 21:29 net.sourceforge.subsonic.androidapp.apk
-rw-r--r-- 1 root root 1940806 Jan 25 14:53 org.adwfreak.launcher-1.apk
-rw-r--r-- 1 root root 118220 Jan 15 22:16 org.ajeje.locationspooferpro.apk
-rw-r--r-- 1 root root 723670 Jan 17 16:16 org.connectbot.apk
-rw-r--r-- 1 root root 63365 Jan 15 21:52 org.jtb.alogcat.apk
-rw-r--r-- 1 root root 1131471 Jan 16 01:05 org.koxx.pure_messenger-2.apk
-rw-r--r-- 1 root root 1764218 Jan 15 19:52 org.pocketworkstation.pckeyboard.apk
-rw-r--r-- 1 root root 335562 Jan 18 18:23 org.prowl.networkmapper.apk
-rw-r--r-- 1 root root 624859 Jan 17 15:29 org.prowl.recorder.apk
-rw-r--r-- 1 root root 2986259 Jan 17 15:27 org.prowl.torque.apk
-rw-r--r-- 1 root root 1229351 Jan 17 15:37 org.prx.talbot.apk
-rw-r--r-- 1 root root 913384 Jan 17 15:32 org.transdroid.apk
-rw-r--r-- 1 root root 41112 Jan 17 15:33 org.transdroid.search.apk
-rw-r--r-- 1 root root 104038 Jan 15 21:54 ru.krikun.freespace.apk
-rw-r--r-- 1 root root 65462 Jan 15 19:51 to.doc.android.ipv6config.apk
-rw-r--r-- 1 root root 53087 Jan 20 00:25 ws.plattner.cifsmanager.apk
-rw-r--r-- 1 root root 2764681 Feb 1 14:55 xcxin.filexpert.apk
-rw-r--r-- 1 root root 161502 Jan 17 17:36 ymst.android.homeswitcher.apk

Apps that, in my testing, didn't work converted to system apps (FC, etc.) included:

SetCPU (overclocking) - .40
Loquendo TTS Susan -- .97
Call Record - .62
Better Terminal (bettertermpro) - .34
OS Monitor - .18
Screencast - 3.14
Sygic (aura) - 5.91
Presto - .52
Tape Machine - 1.28
TuneIn Radio Pro (radiotime.player) - 2.14
Shazam - 3.22
Netflix - 6.63
Plex - 4.17
YouTube - 2.13
Flash Player - 4.48
RockPlayer - 5.5
Port Scanner - .11
Google Goggles (unveil) - 2.23
RealVNC Viewer - 4.46

Under Windows 7 (WinSAT.exe), my SD memory tests out to, best case, ~10MB/s read, and 3MB/s writes:

Windows System Assessment Tool
> Disk Random 4.0 Read 0.73 MB/s
> Disk Random 512.0 Read 9.73 MB/s
> Disk Random 1024.0 Read 10.21 MB/s

> Disk Random 4.0 Write 0.71 MB/s
> Disk Random 512.0 Write 2.29 MB/s
> Disk Random 1024.0 Write 2.89 MB/s

Using dd on a Mac for a write test -- (dd if=/dev/zero of=/Volumes/HTCHD2SD/test.file bs=1024k count=512) -- I get similar ~3 MB/s writes.

Does it sound like I should invest in a new SD card?

After booting, both OS Monitor and System Tuner Pro report ~200mb free. I have, however, seen this number get as low as 40mb free. Is there a low limit where performance dies? Is there a tool, other than 'ps', that I should use to track down memory hogs?

Thanks much for any input.